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1000 Sentences With "main sequence star"

How to use main sequence star in a sentence? Find typical usage patterns (collocations)/phrases/context for "main sequence star" and check conjugation/comparative form for "main sequence star". Mastering all the usages of "main sequence star" from sentence examples published by news publications.

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"F-type main sequence star KIC 8462852" should already ring a bell.
It was also among the first potentially rocky worlds orbiting a main sequence star (a star like our Sun).
"Observationally, there is zero precedent for any main sequence star to vary in brightness like this," Schaefer told Gizmodo.
Redback pulsars are compact binary systems in which a spinning neutron star is closely orbited by a low-mass main sequence star.
That means small, rocky worlds orbiting in the habitable zone of a so-called main sequence star, one that's fusing hydrogen in its core.
Through their calculations, the group at Warsaw University suggests there are no more than 0.25 rogue Jupiter-mass planets per Milky Way main-sequence star.
The star is still building up its mass and will eventually mature into a main sequence star, meaning it will commence nuclear fusion of hydrogen.
When Mercury is intensely backlit by the fury of our main-sequence star, for instance, it's a lot easier to pick out features about its surroundings.
At the same time, the team posits rogue planets similar to Earth's mass could be pretty abundant—possibly as many as two rogue Earth-sized planets per main sequence star.
More specifically, they think that there should be at least 2,000 objects, ranging from moon- to Jupiter-sized, per main-sequence star in the galaxy, based on how the galaxy's gravity warped the objects behind it.
He noted that the most common stars in the galaxy aren't like the Sun, but are cooler, dim M-dwarfs, as opposed to our sun, a hotter G-type main sequence star (sometimes called a yellow dwarf).
While the paper conspicuously avoids speculating about whether or not the aliens are accomplishing this via a so-far unknown controlled dark matter quenching mechanism or, more realistically, just a bunch of ice hurled by the controlled detonation of one or even several frozen moons, it declares in no uncertain terms that the brightness of the F-type main sequence star KIC 113 decreased monotonically over a four year period of observation via NASA's Kepler planet-stalking space telescope, for a total .
WASP-36 is a yellow main sequence star in the Hydra constellation.
Chi1 Orionis is an unrelated, yellow, main sequence star over two degrees away.
It is also a K-type main-sequence star with a mass of .
WASP-25 is a yellow main sequence star in the constellation of Hydra.
WASP-26 is a yellow main sequence star in the constellation of Cetus.
WASP-29 is an orange main sequence star in the constellation of Phoenix.
Kepler-71 is a yellow main sequence star in the constellation of Cygnus.
WASP-37 is a yellow main sequence star in the constellation of Virgo.
Qatar 1 is an orange main sequence star in the constellation of Draco.
The brighter member of the pair, component B, is a seventh magnitude F-type main- sequence star with a class of F4 V, while its companion is an eleventh magnitude K-type main-sequence star with a class of K2 V.
Around 2.5 billion years old, it was formerly an A-type main sequence star.
From the colour and brightness, it is expected to be a hot main sequence star.
Betelgeuse is a red supergiant that has evolved from an O-type main sequence star. Its core will eventually collapse, producing a supernova explosion and leaving behind a compact remnant. The details depend on the exact initial mass and other physical properties of that main sequence star.
The brighter component is an F-type main sequence star with a visual magnitude of 4.95 and a stellar classification of F0 V. At an angular separation of 37.4 arcseconds is fainter, magnitude 7.75 companion. This is a G-type main sequence star with a classification of G1 V.
Infrared interferometric observations did then find a companion, a likely G5 main sequence star around from the primary.
The tertiary component B is magnitude 7.55 A-type main-sequence star at a separation of from the primary.
At an angular separation of 3.28 arcseconds is a magnitude 8.46 A-type main sequence star with a classification of A0 Vp. Finally, a fourth member of the system is a magnitude 11.0 F-type main sequence star with a classification of F8V at an angular separation of 25.2 arcseconds from the primary.
The inner spectroscopic binary consists of two F-type stars, a subgiant and a main-sequence star. There is a companion star which is a white A-type main- sequence star, with an apparent magnitude of 5.76. It is separated 0.361 arcseconds from the primary and has an orbital period of 16.651 years.
HIP 14810 is a G-type main-sequence star located approximately 165 light-years away in the constellation of Aries.
It is an A-type main sequence star of class A8V. The magnitude difference between the two components is 2.64.
HD 73526 is a G-type main-sequence star. It is about 318 light-years away in the constellation Vela.
CoRoT-4 (formerly known as CoRoT-Exo-4) is a yellow-white dwarf main-sequence star in the constellation Monoceros.
Delta2 Canis Minoris (δ2 CMi, δ2 Canis Minoris) is a main-sequence star in the constellation Canis Minor, about away.
Its companion, Zeta Aurigae B, is a B-type main sequence star of stellar classification B5 V or B7 V.
TOI 732 is an M-type main-sequence star. It is of similar age to Sun and relatively enriched in metals.
As a main sequence star ages, the core temperature will rise, resulting in a steadily increasing contribution from its CNO cycle.
RX Andromedae is a cataclysmic variable system, where a white dwarf with a mass of 0.8 and an M2 main sequence star are rotating around their center of mass. The main sequence star is overfilling its Roche lobe, so the white dwarf is stripping away matter from the companion star and accreting it through an accretion disk.
The spectral type for 21 Camelopardalis is given only as A5 with no published luminosity class. It is treated as a normal main sequence star, although it is calculated to be larger and more luminous than a typical A5 main sequence star. Based upon changes to its proper motion over time, this is a probable astrometric binary.
The hidden star has properties that suggest it is a mid-B main sequence star. The two are separated by , about . The hot main sequence star has a mass of , while the supergiant only has a mass of . The supergiant is deformed by the gravity of the more massive primary star, fills its Roche lobe, and is losing mass.
The phase begins when a molecular cloud fragment first collapses under the force of self-gravity and an opaque, pressure supported core forms inside the collapsing fragment. It ends when the infalling gas is depleted, leaving a pre-main-sequence star, which contracts to later become a main-sequence star at the onset of hydrogen fusion producing helium.
GSC 02652-01324 is an orange dwarf main sequence star approximately 523 light- years away in the constellation of Lyra (the Lyre).
Component C is another B class main sequence star, but cooler and less than a thousand times the luminosity of the sun.
WASP-16 is a magnitude 11 yellow dwarf main sequence star, with characteristics similar to our Sun, located in the Virgo constellation.
HD 97413 is a white main-sequence star located 293 light years away, in the constellation Centaurus. Its apparent magnitude is 6.27.
HD 98176 is a white main-sequence star approximately 343 light years away, in the constellation Centaurus. Its apparent magnitude is 6.46.
HD 84117 is a F-type main sequence star in the constellation of Hydra. It has an apparent visual magnitude of approximately 4.94.
Gliese 445 (Gl 445 or AC +79 3888) is an M-type main sequence star in the northern part of the constellation Camelopardalis.
HD 90156 b is an extrasolar planet which orbits the G-type main sequence star HD 90156, located approximately 73 light years away.
Lupus-TR-3 is a dim magnitude 17 K-type main sequence star approximately 8,950 light-years distant in the constellation of Lupus.
Because of this, they are considered subdwarfs, and are less luminous than a main-sequence star of the same spectral type would be.
Around 4 times as massive as the Sun, it spent much of its life as a main sequence star of spectral type B5V.
Kepler-15 is a G-type main sequence star with a mass of .. It is also known as KOI-128, or KIC 11359879.
Delta1 is a yellow-white F-type giant of magnitude 5.25 located around from Earth. About 360 times as luminous and 3.75 times as massive as the Sun, it is expanding and cooling as it ages, having spent much of its life as a main sequence star of spectrum B6V. Also known as 8 Canis Minoris, Delta2 is an F-type main-sequence star of spectral type F2V and magnitude 5.59 which is distant. The last of the trio, Delta3 (also known as 9 Canis Minoris), is a white main sequence star of spectral type A0Vnn and magnitude 5.83 which is distant.
The constellation's dimmer stars were noted by Johann Bayer, who named eight stars including Alpha and Beta, and John Flamsteed, who numbered fourteen. Procyon is the seventh-brightest star in the night sky, as well as one of the closest. A yellow-white main sequence star, it has a white dwarf companion. Gomeisa is a blue-white main sequence star.
38 Virginis is an F-type main sequence star in the constellation of Virgo. It is around 108 light years distant from the Earth.
Iota Leonis B has a mass approximately 8% greater than that of the Sun. It is a G-type main-sequence star, like the Sun.
Component Aa is a red supergiant and its close companion is a B2 main sequence star. The supergiant is a pulsating variable with a small amplitude and poorly defined period. It is generally given spectral class qualifiers indicating peculiarities and emission, which may be associated with the disc around the hot secondary. Component B, HD 203339, is a B3 main sequence star with a mass around .
In 1999, Upsilon Andromedae became the first main-sequence star known to have multiple planets. Kepler-16 contains the first discovered planet that orbits around a binary main-sequence star system. On 26 February 2014, NASA announced the discovery of 715 newly verified exoplanets around 305 stars by the Kepler Space Telescope. These exoplanets were checked using a statistical technique called "verification by multiplicity".
It is a main-sequence star with a class of K3 V. There is a magnitude +10.98 visual companion, designated component C, located 202 arcseconds away.
In 1949, J. Hopmann catalogued it as a suspected Delta Scuti variable. The secondary is a G-type main- sequence star with a class of G6V.
59 Virginis (e Virginis, HR 5011, Gliese 504) is a G-type main-sequence star, located in constellation Virgo at approximately 57 light-years from Earth.
WASP-36 is a yellow main sequence star of spectral class G2, similar to the Sun. It has an unconfirmed stellar companion with apparent magnitude 14.03.
HD 203030 is a Sun-like K-type main-sequence star. It is likely very young, belonging to 45 million years old IC 2391 open cluster.
The secondary component, designated 24 Cancri B, is a F-type main- sequence star. It itself is a binary, with an orbital period of about 22 years.
RT And, database entry, Combined General Catalog of Variable Stars (GCVS4.2, 2004 Ed.), N. N. Samus, O. V. Durlevich, et al., CDS ID II/250 Accessed on line 2009-06-22. The system consists of a G-type main-sequence star slightly more massive than the Sun, and a K-type main-sequence star slightly less massive; the light curve of this eclipsing binary exhibits secular variations of period and minima.
Iota Cancri is a wide double star. The primary is a yellow-hued G-type bright giant star of magnitude 4.0, located 330 ± 20 light-years from Earth. It spent much of its stellar life as a B-type main sequence star before expanding and cooling to its current state as it spent its core hydrogen. The secondary is a white main sequence star of spectral type A3V and magnitude 6.57.
The brightest star in the HD 131399 system is designated HD 131399 A. Its spectral type is A1V, and it is 2.08 times as massive as the Sun. The two lower-mass stars are designated HD 131399 B and C, respectively. B is a G-type main- sequence star, while HD 131399 C is a K-type main-sequence star. Both stars are less massive than the Sun.
The system is a source for X-ray emission, which is most likely coming from the lower mass companion – it may even be a pre-main- sequence star.
HD 233731 is a G-type main-sequence star about 267 light-years away. It has a suspected stellar companions and hosts one known planet, HAT-P-22b.
The primary component is of visual magnitude 6.23 and is a chemically-peculiar F-type main-sequence star with a class of F1Vp. The companion is of magnitude 8.13.
HD 103197 b (also known as HIP 57931 b) is an extrasolar planet which orbits the K-type main sequence star HD 103197, located approximately 170 light years away.
The secondary, β Crucis B, may be a main sequence star with a stellar class of B2. In 2007, a third companion was announced, which may be a low mass, pre-main sequence star. The X-ray emission from this star was detected using the Chandra X-ray Observatory. Two other stars, located at angular separations of 44 and 370 arcseconds, are likely optical companions that are not physically associated with the system.
The two components of 53 Aurigae orbit each other every 39 years with an eccentricity of 0.557. The primary component, 53 Aurigae A, is chemically peculiar since it contains higher-than-normal amounts of manganese, but also europium, chromium, and mercury. It is a B-type main-sequence star, while the secondary component, 53 Aurigae B, is an early F-type main-sequence star. The total mass of the system is estimated to be .
The more luminous member is a B-type main-sequence star with a stellar classification of B9V. Its fainter companion is an F-type main-sequence star with a class of F0Vn, where the 'n' suffix indicates that the metal absorption lines in its spectrum are unusual broad ("nebulous") and indicative of rapid rotation. Based upon discrepancies in the proper motion measurements, there are hints of a third member of this system.
Gamma Ceti appears to be a triple star system. The inner pair (A and B) have an angular separation of 2.6 arcseconds. The primary component of this pair (A) is an A-type main sequence star with a stellar classification of A3 V and a visual magnitude of 3.6. The fainter secondary component (B) is an F-type main sequence star that has a classification of F3 V and a magnitude of 6.6.
Vizier catalog entry The primary, with an apparent magnitude of 4.69, is an F-type main-sequence star with a stellar classification of F6V. It has 35% more mass than the Sun and 188% of the Sun's radius. The star is spinning with a projected rotational velocity of 9.6 km/s. The secondary companion, with an apparent magnitude of 6.12, is a G-type main- sequence star with a class of G2V.
Also possibly a member of this class is Zeta Ursae Minoris, a white star of spectral type A3V, which has begun cooling, expanding and brightening. It is likely to have been a B3 main-sequence star and is now slightly variable. At magnitude 4.95 the dimmest of the seven stars of the Little Dipper is Eta Ursae Minoris. A yellow-white main-sequence star of spectral type F5V, it is 97 light-years distant.
HD 70060 is a class A8V (white main-sequence) star in the constellation Puppis. Its apparent magnitude is 4.45 and it is approximately 93.4 light years away based on parallax.
HD 65810 is a class A2V (white main-sequence) star in the constellation Puppis. Its apparent magnitude is 4.61 and it is approximately 241 light years away based on parallax.
HD 64740 is a class B1.5V (blue main-sequence) star in the constellation Puppis. Its apparent magnitude is 4.63 and it is approximately 760 light years away based on parallax.
The companion would be 6.7 magnitudes fainter than the supergiant primary, cooler and fainter than an F0 main sequence star. The two stars are separated by 2.1 milli-arc seconds.
The primary component is spinning rapidly, with a projected rotational velocity of 217 km/s. It has a stellar classification of A3V, making it an A-type main sequence star.
The primary member, component A, is a white-hued A-type main sequence star with an apparent magnitude of +5.02. Its companion, component B, has an apparent magnitude of +7.39.
The magnitude 8.85 companion, component B, is a G-type main-sequence star. It has a classification of , with the suffix indicating an underabundance of iron in the star's photosphere.
The system is a probable member of the Sco OB2 association of co-moving stars. The visible component is a B-type main-sequence star with a stellar classification of B9V.
K2-58 (also designated as EPIC 206026904) is G-type main-sequence star. The planetary system has three confirmed exoplanets (named as K2-58 b, K2-58 c, K2-58 d).
Kepler-296 is a binary star system in the constellation Draco. The primary star appears to be a late K-type main-sequence star, while the secondary is a red dwarf.
The primary component, designated 48 Cassiopeiae A, is a white A-type main-sequence star with a stellar classification of A2 V and an apparent magnitude of +4.65. It has a companion, component B, which is an F-type main-sequence star of class F2 V and an apparent magnitude of +6.74. This pair orbit around their common centre of mass once every 61.1 years. They have a semimajor axis of 0.614 arcseconds and an eccentricity of 0.355.
The primary component of the system has a stellar classification of B9.5 V, indicating that it is a B-type main sequence star. The companion is an F-type main sequence star with a classification of F9 Ve, where the 'e' indicates that there are emission lines in the spectrum. The two stars are separated by 11 arcseconds. Delta Antliae A, the brighter member of this system, has an estimated 3.4 times the mass of the Sun.
The outburst may have been the result of a so-called mergeburst, the merger of two main sequence stars (or an main sequence star and a pre-main sequence star). This model is strengthened by the apparent youth of the system and the fact that multiple stellar systems may be unstable. The less massive component may have been in a very eccentric orbit or deflected towards the massive one. Computer simulations have shown the merger model to be plausible.
They appear to have an orbital period of three years and an eccentricity of roughly 0.16. As of 2012, the pair have an angular separation of 78.7 mas, which corresponds to a projected separation of 3.6 AU. The primary member, component A, is an A-type main sequence star with a stellar classification of A6 V. The secondary, component B, has an inferred class of F0 V, which would indicate it is an F-type main sequence star.
10 Aquarii (abbreviated 10 Aqr) is an A-type main-sequence star in the constellation of Aquarius. 10 Aquarii is the Flamsteed designation. It is approximately 400 ly from Earth, based on parallax.
The primary is a K-type main sequence star with a stellar classification of K1 Vp. (The 'p' indicates some type of peculiarity with the spectrum.) The companion is a suspected white dwarf.
Tau5 Serpentis, Latinized from τ5 Serpentis, is a F-type main sequence star in the constellation of Serpens, approximately 160 light-years from Earth. It has an apparent visual magnitude of approximately 5.938.
The visible component is an F-type main-sequence star with a stellar classification of F2 V. It is around 2.3 billion years old with a projected rotational velocity of 48 km/s.
Lambda Scorpii is located some 570 light-years away from the Sun. Spectroscopic and interferometric observations have shown that it is actually a triple star system consisting of two B-type stars and a pre-main-sequence star. The primary star is a Beta Cephei variable star with rapid brightness changes of about a hundredth of a magnitude. The pre-main-sequence star has an orbital period of 6 days and the B companion has a period of 1053 days.
Nu Andromedae is the prominent blue star in the upper right of this image. At the center is the Andromeda Galaxy Nu Andromedae is spectroscopic binary system with a nearly circular orbit that has a period of 4.2828 days. The primary component is a B-type main sequence star with a stellar classification of B5 V. The fainter secondary has a classification of F8 V, which makes it an F-type main sequence star. The pair is about 63 million years old.
Beta Circini, Latinized from β Circini, is an A-type main sequence star and is the second-brightest star in the constellation of Circinus. It has an apparent visual magnitude of approximately 4.069, which is bright enough to be viewed with the naked eye. Based upon an annual parallax shift of 35.17 mas as seen from the Earth, it is located about 93 light years from the Sun. With a stellar classification of A3 Va, this is an A-type main-sequence star.
The system most likely contains four stars with two other telescopic components of apparent magnitude 7.2 and 8.2 at angular separations of 0.8 and 6.4 arcseconds from the main pair. The closer (Zeta Phoenicis B) is an A-type main-sequence star with an orbital period around the main pair of about 210 years, as well as an eccentricity of about 0.35.. The further (Zeta Phoenicis C) is an F-type main- sequence star with an orbital period of over 5,000 years.
This is an F-type main sequence star with a stellar classification of F7V and an effective temperature of 6,352 Kelvin. It has a mass of 1.1 solar masses. It is an irregular variable.
This has a spectral class of K1 V, indicating that it is a K-type main sequence star. It is a member of the Local Association, and is most likely a thin disk star.
HD 128311 or HN Boötis is an orange main-sequence star located approximately 54 light-years away in the constellation of Boötes. Two extrasolar planet candidates have been detected in orbit around this star.
HIP 57274 is a K-type main-sequence star in the constellation Ursa Major. It has an apparent magnitude of 8.96 and is both smaller and less luminous than the sun. Three planets orbit it.
GSC 03949-00967 is a G-type main-sequence star about 1190 light-years away. The star is older than Sun, yet is enriched by heavy elements compared to Sun, having 160% of solar abundance.
The first circumbinary planet around a main sequence star was found in 2005 in the system HD 202206: a Jupiter-size planet orbiting a system composed of a Sun- like star and a brown dwarf.
The two stars are close enough that periodic Doppler shifts in their spectra can be made out. In this case, light from both stars can be detected (and they overlap in the spectrum), so it is a double-lined system. The primary star, designated HD 25555, is a K-type bright giant, and the secondary star, designated HD 25556, is a B-type main-sequence star. However, the spectrum has also been interpreted as a G-type star and an A-type main- sequence star.
The secondary is observed to have a spectral type of B5.5 and is expected to be a main sequence star with an absolute magnitude of −1\. However, the brightness difference between a G2 supergiant and a B5.5 dwarf is expected to be larger. It is unclear whether the primary is not a supergiant or the secondary is brighter than a main sequence star. As of 2004, the secondary is located at an angular separation of 0.418 arcseconds along a position angle of 76.7° from the primary.
The primary component is a B-type main sequence star with a stellar classification of B1.5 V. It has 8.5 times the mass of the Sun and 4.1 times the Sun's radius. The secondary is a smaller B-type main sequence star with a classification of about B6.5 V, having 5.3 times the Sun's mass and 4.4 times the radius of the Sun. The effective temperature of the outer atmosphere for each star is 23,725 K for the primary and 16,850 K for the secondary.
Compared to the Sun, the primary, Zeta Tauri A, is an enormous star with more than 11 times the mass and 5–6 times the radius. It is rotating rapidly with a projected rotational velocity of . The companion, Zeta Tauri B, has about 94% the mass of the Sun, although it is unknown whether this is a main sequence star, a neutron star, or a white dwarf. If it is a main sequence star, then the mass indicates it may have a stellar classification of G4.
The primary, Zeta Piscium A, is a pair of A-type subgiant stars with an angular separation of 0.15 arcseconds and visual magnitude 5.28. The secondary, Zeta Piscium B, is a spectroscopic binary with a period of 9.075 days and an eccentricity of 0.04. Together, components Ba and Bb have a combined visual magnitude of 6.43 and lie at an angular separation of 22.9 arcseconds from the primary. They are a F-type main sequence star and a G-type main sequence star, respectively.
HD 89307 is a yellow main-sequence star located approximately 108 light-years away in the constellation of Leo. The apparent magnitude is 7.06. The mass of the star is identical in value to the Sun.
It has sometimes been classified as a main sequence star and sometimes as a giant star. The Galactic O-Star Spectroscopic Survey has used it as the standard star for the newly created O4 subgiant spectral type.
However, X-ray emission, variations in luminosity, and levels of lithium may indicate that this is instead a weak-lined T Tauri star—a low mass pre-main sequence star that is relatively poor in circumstellar matter.
WASP-76, also known as BD+01 316, is a yellow-white main sequence star in the constellation of Pisces. Since 2014, it has had one suspected stellar companion at a projected separation of 85 astronomical units.
This is a double-lined spectroscopic binary star system. The spectrum matches a B-type main-sequence star with a stellar classification of B2.5 V. There is a faint visual companion with an apparent magnitude of 12.49.
The star is moving closer to the Sun with a radial velocity of −12 km/s. It is a member of the Ursa Major Moving Group of stars that share a common motion through space. The star was assigned a stellar classification of F0 V by Nancy Roman in 1949, indicating it is an F-type main-sequence star. However, in 1995 Abt and Morrell catalogued it as class ; a somewhat hotter and more massive A-type main- sequence star that displays spectral peculiarities as well as nebulous lines brought about by rapid rotation.
The terms giant and dwarf were coined for stars of quite different luminosity despite similar temperature or spectral type by Ejnar Hertzsprung about 1905. Giant stars have radii up to a few hundred times the Sun and luminosities between 10 and a few thousand times that of the Sun. Stars still more luminous than giants are referred to as supergiants and hypergiants. A hot, luminous main-sequence star may also be referred to as a giant, but any main-sequence star is properly called a dwarf no matter how large and luminous it is.
HD 158633 is a main sequence star in the northern constellation Draco. With an apparent visual magnitude of 6.43, this star is too faint to be observed with the unaided eye but it can be seen with a small telescope. Based upon parallax measurements made by the Hipparcos spacecraft, it is located around 42 light years from the Sun. This is a K-type main sequence star with a spectral classification of K0 V. It has about 79% of the Sun's radius and 73% of the solar mass.
This is most likely (98.7% chance) a member of the TW Hydrae association. This is a rapidly rotating A-type main-sequence star that is about double the mass of the Sun. It emits 20.66 times as much energy as the Sun, at an effective temperature of 8,954 K. HD 96819 is currently 31.5% through its life as a main-sequence star: after that it will swell up as a red giant. It is a young star of around nine million years age, and is a suspected variable star.
The magnitude 5.79 primary component is a B-type main-sequence star with a stellar classification of B9V. This star is 150 million years old with three times the mass of the Sun. It is radiating 91 times the Sun's luminosity from its photosphere at an effective temperature of 11,402 K. At an angular separation of is a K7.9 type secondary companion, a possible X-ray source. The third component is an F-type main-sequence star of class F3V and magnitude 8.13, located at a separation of .
S Coronae Australis (S CrA), is a young binary star system estimated to be around 2 million years old located in the constellation Corona Australis. It is composed of a G-type main sequence star that is about as luminous as and just over twice as massive as the Sun, and a smaller K-type main sequence star that has around 50-60% of the Sun's luminosity and 1.3 times its mass. Both stars are T Tauri stars and both show evidence of having circumstellar disks. The system is around 140 parsecs distant.
HD 103774 is a young yellow-white main-sequence star of apparent magnitude 7.12 that is 181 ± 5 light-years distant from Earth. It is 1.335 ± 0.03 times as massive and 3.5 ± 0.3 as luminous as the Sun.
The fourth component, 5 Aquilae B, is a magnitude 7.65 F-type main sequence star with a stellar classification of F3 Vm. It is at an angular separation of 12.71 arcseconds from the other members of the system.
This has caused the star to expand and become cooler than a comparable main sequence star. Its physical properties show it to be near the end of the subgiant branch and about to join the red giant branch.
Its mass is roughly half that of the planet Mercury. The smallest known planet orbiting a main-sequence star other than the Sun is Kepler-37b, with a mass (and radius) slightly higher than that of the Moon.
The smaller companion bears the variable star name GQ Andromedae. It's a red dwarf main sequence star that undergoes flare events like the primary; it has a spectral type M4.1, so it has also a lower effective temperature.
54 Aquarii (abbreviated 54 Aqr) is a faint, white-colored main-sequence star in the constellation of Aquarius. 54 Aquarii is its Flamsteed designation. It is about 270 light-years, or 78 parsecs from Earth, based on its parallax.
Matter is being energetically accreted from the main sequence star onto one or both magnetic poles of the white dwarf star, producing emission lines in the spectrum. The magnetic field of the white dwarf has an estimated strength of .
HD 93607 (HR 4222) is a star in the constellation Carina. Its apparent magnitude is 4.87. Its parent cluster is IC 2602. HD 93607 is a B4 main sequence star, although older spectral studies classified it as a subgiant.
SU Aurigae's proper motion and distance is similar to AB Aurigae, a better known pre-main-sequence star, meaning that the two may form a very wide binary system; if not, they are still in the same star association.
HD 130917 is a single star in the northern constellation of Boötes. It is an A-type main sequence star with a stellar classification of A4V. At an apparent magnitude of 5.80, it is visible to the naked eye.
HD 113538 (Gliese 496.1) is a K-type main-sequence star of a late spectral type (K9V) that lies approximately 51 light-years away in the constellation of Centaurus. The star was announced to have a planetary system in 2010.
AM CVn variables are symbiotic binaries where a white dwarf is accreting helium-rich material from either another white dwarf, a helium star, or an evolved main-sequence star. They undergo complex variations, or at times no variations, with ultrashort periods.
The visible component is an F-type main sequence star with a stellar classification of F6 V. It is around 2.4 billion years old and has a high abundance of elements other than hydrogen and helium when compared to the Sun.
The third-brightest star is 21 Leonis Minoris, a rapidly rotating white main-sequence star of average magnitude 4.5. The constellation also includes two stars with planetary systems, two pairs of interacting galaxies, and the unique deep-sky object Hanny's Voorwerp.
HD 86264 is a 7th magnitude F-type main sequence star located approximately 224 light years away in the constellation Hydra. The survey in 2015 have ruled out the existence of any stellar companions at projected distances above 30 astronomical units.
It was entered into the General Catalogue of Variable Stars in 1997. Gliese 908 is a cool main sequence star, a red dwarf, with a spectral class of M1V Fe-1. The suffix indicates a noticeable deficiency in heavy elements.
It is radiating 176 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,349 K. The companion star, component B, is most likely a lower main sequence star with 0.6–0.8 times the Sun's mass.
ESO image. A star becomes a giant after all the hydrogen available for fusion at its core has been depleted and, as a result, leaves the main sequence. The behaviour of a post-main-sequence star depends largely on its mass.
Starspots cover about 40% of its surface. The star produces intense flares observable at all wavelengths. Its smaller companion (II Pegasi B) is too close to have been observed directly. It is a red dwarf, an M-type main sequence star.
HD 93194 (HR 4205) is a star in the constellation Carina. Its apparent magnitude is 4.79. Its parent cluster is IC 2602. HD 93607 is a B4 main sequence star, notable for "nebulous" absorption lines caused by its rapid rotation.
Component B is a magnitude 7.57 B-type main sequence star with a class of B8.5 V. It has 2.6 times the Sun's mass and 2.16 times the radius of the Sun. The star is filling 60% of its Roche radius.
K2-19 is a early K-type or late G-type main sequence star that is magnetically active, and has a light curve that exhibits variations in brightness of ~1%. Three confirmed transiting exoplanets are known to orbit this star.
WASP-4 is a G-type main sequence star approximately 880 light-years away in the constellation of Phoenix. Despite its advanced age, the star is rotating rapidly, being spun up by the tides raised by giant planet on close orbit.
HD 12661 is a G-type main sequence star in the northern constellation of Aries. The star is slightly larger and more massive than the Sun, with an estimated age of seven billion years. It has two known extrasolar planets.
It has around double the mass, 7.8 times the radius and 36 times the luminosity of the Earth's Sun. Separated by 0.1 to 0.6 second of arc from the primary, the secondary is a yellow-white main sequence star of spectral type F8. The two orbit around a common centre of gravity every 38.62 years, and lie away from the Solar System. Around away and around 10 times as luminous as the Sun, 21 Leonis Minoris is a rapidly rotating white main- sequence star, spinning on its axis in less than 12 hours and very likely flattened in shape.
The primary, component A, is an evolved K-type giant star with a stellar classification of F3 III. However, Houk and Swift (1999) listed a classification of F0 V, which would match an F-type main sequence star. It displays an infrared excess at a wavelength of 70 μm and thus is a candidate host of an orbiting debris disk. The common proper motion companion, component B, is a G-type main sequence star with a classification of G3 V. It is a BY Draconis variable with a periodicity of 8.92 days and a variable star designation of EZ Cet.
The Wolf–Rayet star that produces the characteristic emission line spectrum of WR 104 has a resolved companion and an unresolved spectroscopic companion, forming a triple system. The spectroscopic pair consists of the Wolf–Rayet star and a B0.5 main sequence star. The WR star is visually 0.3 magnitudes fainter than the main sequence star, although the WR star is typically considered the primary, as it dominates the appearance of the spectrum and is more luminous. The two are in a nearly circular orbit separated by about 2 AU, which would be about one milli-arcsecond at the assumed distance.
Polaris components as seen by the Hubble Space Telescope Polaris Aa is a 5.4 solar mass () F7 yellow supergiant of spectral type Ib. It is the first classical Cepheid to have a mass determined from its orbit. The two smaller companions are Polaris B, a F3 main-sequence star orbiting at a distance of (AU), and Polaris Ab (or P), a very close F6 main-sequence star with a mass of . Polaris B can be seen with a modest telescope. William Herschel discovered the star in August 1779 using a reflecting telescope of his own, one of the best telescopes of the time.
Located near Alpha is Delta Antliae, a binary star, 450 ± 10 light-years distant from Earth. The primary is a blue- white main sequence star of spectral type B9.5V and magnitude 5.6, and the secondary is a yellow-white main sequence star of spectral type F9Ve and magnitude 9.6. Zeta Antliae is a wide optical double star. The brighter star—Zeta1 Antliae—is 410 ± 40 light-years distant and has a magnitude of 5.74, though it is a true binary star system composed of two white main sequence stars of magnitudes 6.20 and 7.01 that are separated by 8.042 arcseconds.
The pair are members of the Tucana-Horologium moving group, a 45 million year old set of stars that share a common motion through space. HD 24071 is an A-type main- sequence star with a stellar classification of A1 Va. It is a suspected variable star of unknown type showing an amplitude of 0.05 magnitude, and is a source of X-ray emission, which may originate from a companion of class G2-5V. The brighter component, HD 24072, is a B-type main-sequence star with a classification of B9.5 Van. The n suffix indicates "nebulous" absorption lines due to rapid rotation.
K2-33 is an extremely young pre-main-sequence star located about away from the Earth in the constellation of Scorpius. It is known to host one planet, a super-Neptune, named K2-33b. It is also notable for its young age.
107 Piscium (abbreviated 107 Psc) is a K-type main sequence star in the constellation of Pisces, about 24.4 light years away from the Earth. 107 Piscium is the Flamsteed designation. It has an apparent visual magnitude which varies between 5.14 and 5.26.
HAT-P-26 is a K-type main-sequence star about 302 light-years away. Survey in 2015 did not find any stellar companions on orbit around it, although a red dwarf companion with a temperature 4000 K is suspected on wide orbit.
M47 on the left. KQ Puppis (KQ Pup) is a spectroscopic binary variable star in the constellation Puppis. A red supergiant star and a hot main sequence star orbit each other every 9,742 days. Its apparent magnitude varies between 4.82 and 5.17.
The orbital period of the system is 5.28 days, and the eccentricity of the system is 0.00220, implying a nearly circular orbit. The primary has a mass of , and is an F-type main-sequence star. The secondary is less massive, at .
Theta Boötis (θ Boo, θ Boötis) is a main sequence star in the constellation Boötes, about 47 light years away. It has the traditional name Asellus Primus (Latin for "first donkey colt")Star Name - R.H.Allen p.105 and the Flamsteed designation 23 Boötis.
With an age of roughly 6 billion years,Smallest Alien Planet Kepler-37b Explained (Infographic) it is slightly older than the Sun, but is still a main-sequence star. Until January 2015, Kepler-37 was the smallest star to be measured via asteroseismology.
It is classified as an α² CVn type variable star and its brightness varies by 0.04 magnitudes with a period of 2.61 days. The secondary, γ¹ Arietis, is a magnitude 4.58 B-type main-sequence star with a stellar classification of B9 V.
HIP 5158 b is an extrasolar planet which orbits the K-type main sequence star HIP 5158, located approximately 130 light years away in the constellation Cetus. This planet was detected by HARPS on October 19, 2009, together with 29 other planets.
It has an effective temperature of 15,135 K and an estimated mass six times that of the Sun. The companion, component B, is an F-type main sequence star with a stellar classification of F8 V. It has an effective temperature of 4,786 K.
The magnitude 7.43 secondary companion, component B, is a suspected variable star and may be a Delta Scuti variable. Alternatively, it may be an ellipsoidal variable with a brown dwarf companion. It is an F-type main-sequence star with a class of F1V/F4.
Gliese 167 is a star in the constellation Dorado. It has an apparent magnitude of 7.634. Based on parallax measurements by Gaia, the star is known to be located 42.5 light-years (13.02 parsecs) away. The star is a K-type main- sequence star.
SDSS J001820.5–093939.2 or SDSS J0018−0939 for short is a star system approximately 1000 light-years away near the constellation Cetus. SDSS J0018−0939 is a cool main-sequence star. It is the first star found proposed to be a massive second generation star.
Rho Aquilae is an A-type main sequence star with a stellar classification of A2 V. This star is about 50 to 120 million years old and it displays an excess emission of infrared radiation that may be explained by a circumstellar disk of dust.
KIC 11026764 is a G-type main sequence star whose characteristics have been extensively measured by the Kepler spacecraft because of its similarity to our Sun. Its diameter is 2.18 times the Sun and is aged at 5.94 billion years, slightly older than our Sun.
HAT-P-18 is a K-type main-sequence star about 530 light-years away. The star is very old and has a concentration of heavy elements similar to solar abundance. A survey in 2015 detected very strong starspot activity on HAT-P-18.
Pi Mensae b (π Men b, π Mensae b), also known as HD 39091 b, is an extrasolar planet approximately 59 light-years away in the constellation of Mensa. The planet was announced orbiting the yellow main-sequence star Pi Mensae in October 2001.
According to Gray et al. (2003), the primary component has a stellar classification of A5 V, matching an A-type main-sequence star. Cowley et al. (1969) had assigned it to a class of A4 IVs, suggesting it is a sharp-lined (s) subgiant star.
The brightest star, is a young A-type main-sequence star, and further out are two lower-mass stars. A Jupiter-mass planet or a low-mass brown dwarf was once thought to be orbiting the central star, but this has been ruled out.
WASP-49 is a yellow dwarf main-sequence star. Its surface temperature is 5600 K. WASP-49 is depleted of heavy elements relative to Sun, with metallicity Fe/H index of -0.23, meaning it has an abundance of iron 59% of the Sun's level.
The orbital period of the system is 19.41 days, and the eccentricity of the system is 0.19494, implying a slightly elliptical orbit. The primary has a mass of , and is a G-type main-sequence star or subgiant. The secondary is less massive, at .
Vizier catalog entry Vizier catalog entry The combined spectrum matches a stellar classification of A7 V, which would normally indicate an A-type main-sequence star that is generating energy through hydrogen fusion at its core. It has an estimated age of 717 million years.
HD 153791 is a double star in the southern constellation of Ara. The primary is a sixth magnitude A-type main sequence star. It has a magnitude 12.3 companion at an angular separation of 6.0″ along a position angle of 249°, as of 1999.
The system is a member of the Perseus OB2 association of co-moving stars. The primary component is a massive B-type main-sequence star with a stellar classification of B0.5V. It is about 7.2 million years old and has a very low projected rotational velocity for an early B-type star, measured at 10 km/s. This star has 12.5 times the mass of the Sun and is radiating 936 times the Sun's luminosity from its photosphere at an effective temperature of 29,330 K. The companion is magnitude 10.04, A-type main-sequence star with a class of A1Vn, and is located at an angular separation of from the primary.
Located about 97 light-years away from Earth, Alpha Pictoris is the brightest star in the constellation; it is a white main-sequence star with an apparent magnitude of 3.3, and spectral type A8VnkA6. A rapidly spinning star with a projected rotational velocity estimated at 206 km/s, it has a shell of circumstellar gas. Beta Pictoris is another white main sequence star of spectral type A6V and apparent magnitude 3.86. Located around 63.4 light-years distant from Earth, it is a member of the Beta Pictoris moving group—a group of 17 star systems around 12 million years old moving through space together.
XO-1 is a magnitude 11 yellow main-sequence star located approximately light-years away, of spectral type G1V with a mass and radius similar to the Sun. In 2006 the hot Jupiter exoplanet XO-1b was discovered orbiting XO-1 by the transit method using the XO Telescope. Roughly the size of Jupiter, it completes an orbit around its star every three days. The discovery of a Jupiter-sized planetary companion was announced in 1997 via analysis of the radial velocity of Rho Coronae Borealis, a yellow main sequence star and Solar analog of spectral type G0V, around 57 light-years distant from Earth.
Xi lies 2 degrees northeast, and is a yellow-white main sequence star of spectral type F6V that is 86% larger and 17% more massive that the Sun, and radiate 4.5 times the solar luminosity. It has a red dwarf companion that is 192.3 au distant. If (as is likely) the smaller star is in orbit around the larger star, then it would take around 2000 years to complete a revolution. Theta Pegasi marks the horse's eye. Also known as Biham, it is a 3.43-magnitude white main sequence star of spectral type A2V, around 1.8 times as massive, 24 times as luminous, and 2.3 times as wide as the Sun.
The two stars have an estimated physical separation of . The magnitude 6.09 primary component is a B-type main-sequence star with a stellar classification of B9 V. It has 2.73 times the Sun's radius and is radiating 84 times the Sun's luminosity from its photosphere at an effective temperature of 10,870 K. It is spinning with a projected rotational velocity of 176 km/s. The secondary is a magnitude 6.82 A-type main-sequence star with a class of A1 Vn, where the 'n' suffix indicates "nebulous" lines due to rapid rotation. It is spinning with a high projected rotational velocity of 233 km/s.
The companion star has a classification of A2 V, so it is a main sequence star that is generating energy through the thermonuclear fusion of hydrogen at its core. This star is rotating rapidly, with a projected rotational velocity of 123km/s. By the time the smaller main sequence star reaches the current point of the primary in its evolution, the larger star will have lost much of its mass in a planetary nebula and will have evolved into a white dwarf. The pair will have essentially changed roles: the brighter star becoming the dim dwarf, while the lesser companion will shine as a giant star.
VY Canis Majoris is a highly evolved star with an age less than 10 Myr although some older authors argued that it would rather either be a very young protostar or a massive pre-main-sequence star with an age of only 1 Myr and also a circumstellar disk around the star. It has probably evolved from an O9 main sequence star with a radius of . The star has evolved rapidly because of its high mass. The time spent to the red hypergiant phase is estimated to be between 100,000 and 500,000 years, and thus VY CMa had left its main sequence more than a million years ago.
As of 2013, the two components had an angular separation of along a position angle of 246°. This corresponds to a projected separation of . The magnitude 4.95 primary, designated component A, is a chemically peculiar B-type main-sequence star with a stellar classification of B9V It has 3.4 times the Sun's mass and is radiating around 268 times the luminosity of the Sun from its photosphere at an effective temperature of 10,910 K. Component B, the magnitude 7.71 secondary, is an A-type main-sequence star with a class of A3V. It is smaller than the primary, but has a higher projected rotational velocity.
As a result of a 1997 lunar occultation, a companion star was discovered at an angular separation of 21 mas. It appears to be an A-type main sequence star with a class of around A5. This companion was not detected during prior occultations by the Moon.
The primary, component A, is a K-type main-sequence star with a stellar classification of K1V and a visual magnitude of 8.82. Torres et al. (2006) classed it as a K1IV star, suggesting it is a subgiant star that is evolving off the main sequence.
HAT-P-19 is a K-type main-sequence star about 650 light-years away. The star is old yet metal enriched, having amount of heavy elements 250% of solar abundance. The survey in 2012 have failed to find any stellar companions to HAT-P-19.
As of 2018, they had an angular separation of along a position angle of 30°. The brighter member, component A, is a B-type main-sequence star with a stellar classification of B1V. The secondary, component B, is of class B3V. Both stars are spinning rapidly.
The wind is being effected by the star's rapid rotation, resulting in an enhanced outflow along the equator. Gamma Arae has an optical companion located at an angular separation of 17.9 arcseconds, which is an A-type main sequence star with an apparent magnitude of 10.5.
Upsilon Aquarii is an F-type main sequence star with a stellar classification of F5 V. With an effective temperature of 6,597, it shines with the yellow-white hue of an F-type star. An orbiting companion star was detected in 2007 at the Gemini Observatory.
51 Pegasi (abbreviated 51 Peg), formally named Helvetios , is a Sun-like star located from Earth in the constellation of Pegasus. It was the first main- sequence star found to have an exoplanet (designated 51 Pegasi b, officially named Dimidium, formerly unofficially dubbed Bellerophon) orbiting it.
It is classified as a rotating ellipsoidal variable star and its brightness varies by 0.02 magnitudes with a period of 23.57 hours, which equals half of its orbital period. The spectrum matches that of an A-type main-sequence star with a stellar classification of A5 V.
CoRoT-7 (TYC 4799-1733-1) is a G-type main sequence star, slightly smaller and cooler than the Sun. It has an apparent magnitude 11.67, fainter than Proxima Centauri (mag. 11.05), the nearest star to the Sun. This star is located in the Monoceros constellation.
Alpha Corvi (α Corvi, abbreviated Alpha Crv, α Crv), also named Alchiba , is an F-type main-sequence star and the fifth-brightest star in the constellation of Corvus. Based on parallax measurements made during the Hipparcos mission, it is approximately 49 light-years from the Sun.
HD 142022 is a binary system, a component of which is a sunlike star with a massive planet with an orbital period of 1928 ± 46 days. HD 212301 is a yellow-white main sequence star with a hot jupiter that completes an orbit every 2.2 days.
Alpha Gruis, Latinized from α Gruis, officially named Alnair , is a single star in the southern constellation of Grus. At magnitude 1.7 it is the brightest star in Grus and one of the brightest stars in the sky. It is a B-type main-sequence star away.
Gray et al. (2006) assigned this star a stellar classification of F5.5 V, matching an ordinary F-type main-sequence star. Older studies, such as Malaroda (1975) or Eggen (1955), listed a class of F5 III-IV or F6 III-IV, suggesting a more evolved condition.
Eta Corvi (Eta Crv, η Corvi, η Crv) is an F-type main-sequence star, the sixth-brightest star in the constellation of Corvus. Two debris disks have been detected orbiting this star, one at ~150 AU, and a warmer one within a few astronomical units (AU).
BD−08°2823 is a 9.86 magnitude K-type main sequence star located approximately 135 light years away in the constellation Sextans. This star is smaller, cooler, fainter, and less massive than the Sun. Also its metal content is six- sevenths as much as the Sun.
HD 42936 is a binary star composed of an orange (K-type) main-sequence star and an L-type dwarf star just massive enough to burn hydrogen, located approximately 153 light-years away in the constellation of Mensa, taking its primary name from its Henry Draper Catalogue designation.
A subgiant is a star that is brighter than a normal main-sequence star of the same spectral class, but not as bright as giant stars. The term subgiant is applied both to a particular spectral luminosity class and to a stage in the evolution of a star.
HD 65216 is an 8th magnitude G-type main sequence star located approximately away in the constellation of Carina. It is a Sun-like yellow dwarf, 8% less massive and somewhat less luminous. It cannot be seen without technical aid, but with binoculars or telescope it should be visible.
HD 187734 is double star in the equatorial constellation of Aquila. The primary is a magnitude 6.6 giant star, while the companion is a magnitude 9.4 A-type main sequence star. As of 2014, the pair had an angular separation of 5″ along a position angle of 99°.
The primary is a red clump giant, a star on the cool end of the horizontal branch fusing helium in its core. The secondary star has begun to evolve off the main sequence; it is sometimes classified as a giant star and sometimes as a main-sequence star.
WASP-35 is a G-type main-sequence star about 660 light-years away. The star age cannot be well constrained, but it is probably older than the Sun. WASP-35 is similar in concentration of heavy elements compared to the Sun. The star has no detectable starspot activity.
HD 33636 is a binary system located approximately 94 light-years away in Orion constellation. The visible member HD 33636 A is a 7th magnitude yellow main- sequence star. It is located at a distance of 91.6 light years from Earth. It has a metallicity of −0.05 ± 0.07.
The stellar classification of 4 Scorpii is A3 V, indicating this is an ordinary A-type main-sequence star. It has 2.6 times the mass of the Sun and is radiating around 92 times the Sun's luminosity from its photosphere at an effective temperature of about 8,356 K.
The magnitude 5.97 secondary, component B, is a single-lined spectroscopic binary star system with an orbital period of 17.4 days and an eccentricity of 0.21. The pair have an angular separation of . The visible component is a B-type main-sequence star with a class of B8 V.
The Sun is the most familiar example of a main-sequence star As non-fusing helium ash accumulates in the core of a main-sequence star, the reduction in the abundance of hydrogen per unit mass results in a gradual lowering of the fusion rate within that mass. Since it is the outflow of fusion-supplied energy that supports the higher layers of the star, the core is compressed, producing higher temperatures and pressures. Both factors increase the rate of fusion thus moving the equilibrium towards a smaller, denser, hotter core producing more energy whose increased outflow pushes the higher layers further out. Thus there is a steady increase in the luminosity and radius of the star over time.
The magnitude 5.78 primary component is an A-type main-sequence star with a stellar classification of A1 V. This star has 2.5 times the mass of the Sun and is radiating 56 times the Sun's luminosity from its photosphere at an effective temperature of 9,863 K. It is 323 million years old and is spinning with a projected rotational velocity of 60 km/s. The system is a source for X-ray emission, which is most likely coming from the companion star. This magnitude 9.60 component is a possible pre-main sequence star with a mass similar to the Sun. It is radiating 76% of the Sun's luminosity at an effective temperature of 6,370 K.
He interpreted the spectrum to be of an F-type main-sequence star, but it is now thought that such a spectrum could be caused by the residue of a nearby exoplanet that had been pulverized into dust by the gravity of the star, the resulting dust then falling onto the star. The first suspected scientific detection of an exoplanet occurred in 1988. Shortly afterwards, the first confirmation of detection came in 1992, with the discovery of several terrestrial-mass planets orbiting the pulsar PSR B1257+12. The first confirmation of an exoplanet orbiting a main-sequence star was made in 1995, when a giant planet was found in a four-day orbit around the nearby star 51 Pegasi.
Six stars with planetary systems have been found. Three planets have been discovered in the system of the orange star HD 181433, an inner super-earth with an orbital period of 9.4 days and two outer gas giants with periods of 2.6 and 6 years respectively. HD 196050 and HD 175167 are yellow G-class Sun-like stars, while HD 190984 is an F-class main sequence star slightly larger and hotter than the Sun; all three are accompanied by a gas giant companion. HD 172555 is a young white A-type main sequence star, two planets of which appear to have had a major collision in the past few thousand years.
The system is moving closer to the Earth with a heliocentric radial velocity of -24.5 km/s. The two components of 39 Draconis have an angular separation of and take almost 4,000 years to orbit each other. The primary star is an early A-type main-sequence star, having 2.12 times the mass of the Sun with a visual magnitude of 5.06 The secondary is a magnitude 8.07 F-type main-sequence star, and has 1.18 times the mass of the Sun. The 8th-magnitude star HD 238865 is listed in double star catalogues as component C. It is separated from the other two stars by and lies at about the same distance.
This star has 1.5 times the mass of the Sun, with a projected rotational velocity of 16 km s−1. It is radiating 8.7 times the luminosity of the Sun from its outer atmosphere at an effective temperature of 6,282 K. The radius is about 2.5 times that of the Sun. Iota Virginis B has not been directly detected, but based on its mass () it may be a main-sequence star or a white dwarf. That star is also responsible for the drifting radial velocity of the primary. In 2011, it was noticed that the faint K-type main-sequence star HD 125354 had a similar proper motion throughout space, and was likely physically associated.
The Catalog of Components of Double and Multiple Stars lists three companions: B is 24 Tauri, a magnitude 6.28 A0 main sequence star 117" away; C is V647 Tauri, a δ Sct variable star; and D is a magnitude 9.15 F3 main sequence star. V647 Tau varies from magnitude +8.25 to +8.30 over 1.13 hours. The Washington Double Star Catalog lists a further four companions, all fainter than 11th magnitude, and also describes component D as itself double with two nearly equal components separated by 0.30". The main star, Alcyone A, consists of three components, the brightest being a blue-white B-type giant similar to many of the other B-type stars in the Pleiades cluster.
Upsilon Andromedae (υ Andromedae, abbreviated Upsilon And, υ And) is a binary star located approximately 44 light-years from Earth in the constellation of Andromeda. The system consists of an F-type main-sequence star (designated υ Andromedae A, officially named Titawin ) and a smaller red dwarf. , four extrasolar planets (designated Upsilon Andromedae b, c, d and e; the first three named Saffar, Samh and Majriti, respectively) are believed to orbit υ Andromedae A. All four are likely to be jovian planets that are comparable in size to Jupiter. This was both the first multiple-planet system to be discovered around a main-sequence star, and the first multiple-planet system known in a multiple star system.
The combined spectra of the two components has a stellar classification of A1V, which matches an A-type main-sequence star. They have magnitudes of +5.0 and +5.6. Both components are Am stars, indicating they appear chemically peculiar. The primary appears to be rotating around 3.5 times faster than the secondary.
HAT-P-25 is a G-type main-sequence star about 990 light-years away. It has a very low flare activity.Evgenya L. Shkolnik, "AN ULTRAVIOLET INVESTIGATION OF ACTIVITY ON EXOPLANET HOST STARS", 2013 The star is enriched in heavy elements, having about twice amount of metals compared to solar abundance.
Lambda Geminorum, Latinized from λ Geminorum, is a class A3, fourth-magnitude star in the constellation Gemini. It is located about 101 light-years from Earth. Lambda Geminorum was a suspected variable star, but is now confirmed as constant. It is a main sequence star, larger and hotter than the sun.
Gliese 86 (13 G. Eridani, HD 13445) is a K-type main-sequence star approximately 35 light-years away in the constellation of Eridanus. It has been confirmed that a white dwarf orbits the primary star. In 1998 the European Southern Observatory announced that an extrasolar planet was orbiting the star.
HD 125612 d is an extrasolar planet which orbits the G-type main sequence star HD 125612, located approximately 172 light years away in the constellation Virgo. The discovery of this planet was announced by the HARPS team on October 19, 2009, together with 31 other planets, including HD 125612 c.
82 G. Eridani (HD 20794, HR 1008, e Eridani) is a star about 20 light years away from Earth in the constellation Eridanus. It is a main-sequence star with a stellar classification of G6 V, and it hosts a system of at least three planets and a dust disk.
An X-ray emission has been detected from the pair. The third component is a visible companion, probably a pre-main-sequence star, at magnitude 13.7 and separation . This star is estimated at 0.15 solar masses and an effective temperature of 3,192 K. It too is an X-ray source.
In addition to the spectroscopic companion there is a visual companion star which shares a common proper motion with Nu Ceti A, designated component B; an F-type main-sequence star with a class of F7V and a 9.08 apparent visual magnitude located 8.0 arcsec away. It was discovered by Struve.
HD 114762 is a binary star system approximately away in the constellation Coma Berenices. It consists of a yellow-white F-type main-sequence star and a red or brown dwarf companion approximately distant. Both are low-metal subdwarfs. A telescope or strong binoculars are needed to view the primary.
HAT-P-7 is a F-type main sequence star located about 1123 light-years away in the constellation Cygnus. The apparent magnitude of this star is 10.5, which means it is not visible to the naked eye but can be seen with a small telescope on a clear dark night.
The orbital plane is inclined 74.5° and the system does not form an eclipsing binary. The primary component is an evolving star currently in the Hertzsprung gap. Its companion is a main sequence star. Both members have more mass than the Sun and they are around 1.5 billion years old.
The primary component of is a magnitude 6.47 giant star with a stellar classification of G8 III:. A companion star at an angular separation of 1.437 arcseconds is an A-type main sequence star with a classification of A1 V. It is slightly fainter, with an apparent magnitude of 6.75.
HD 128093 is a double star in the constellation Boötes. The brighter component is an F-type main sequence star with a stellar classification of F5V and an apparent magnitude of 6.33. It has a magnitude 11.33 companion at an angular separation of 28.1 along a position angle of 318°.
AP Columbae, also known as AP Col, is a pre-main-sequence star in the constellation of Columba, which has been studied for the last 15 years, but was recently discovered to be very young and close to Earth. It has been recognized as the closest young star to the Earth.
The combined spectrum of Psi2 Orionis matches that of a B-type subgiant star with a stellar classification of B2 IV. The primary component is an evolved giant star with a class of B1 III, while the secondary is a B-type main sequence star with a classification of B2 V.
The secondary component is an F-type main sequence star with a classification of F0 V. The secondary star is 3.56 magnitudes fainter that the primary star at 700 nm. There are also 2 class G stars further away that may or may not be physically related to the main pair.
The companion is an A-type main-sequence star with a stellar classification of A3V and visual magnitude 9.2. As of 2008, it had an angular separation of from the primary. There is a faint infrared nebulosity at a separation of from the pair that is most likely a bow shock.
There seems to be agreement that the star system is relatively young. Munari et al. conclude that the system may be only about 4 million years old. The spectrum of V838 Monocerotis reveals a companion, a hot blue B-type main sequence star probably not very different from the progenitor star.
Kochab aside, three more stellar systems have been discovered to contain planets. 11 Ursae Minoris is an orange giant of spectral type K4III around 1.8 times as massive as the Sun. Around 1.5 billion years old, it has cooled and expanded since it was an A-type main sequence star.
This is a G-type main sequence star of class G8. Based upon light variations measured during eclipses by the Kepler spacecraft, the system may contain a third body with twice the mass of Jupiter and an orbital period of under seven years. As of 2015, this remains to be confirmed.
HIP 5158 is a 10th magnitude K-type main sequence star located approximately 130 light years away in the constellation Cetus. This star is smaller, cooler, fainter, and less massive than our Sun, but it is more metal rich, having concentration of heavy elements equal to 125% of solar abundance.
HAT-P-17 is a K-type main-sequence star about away. It has a mass of about . It is the host of two planets, HAT-P-17b and HAT-P-17c, both discovered in 2010. A search for a binary companion star using adaptive optics at the MMT Observatory was negative.
Gliese 69 is a star located in the constellation of Cassiopeia. It has an apparent magnitude of 8.40. Parallax measurements by Hipparcos put it at a distance of 44.3 light-years (13.6 parsecs) away. Gliese 69 is a K-type main- sequence star that is smaller and less massive than the Sun.
HD 85512 is a solitary K-type main-sequence star located approximately 37 light-years away in the constellation Vela. It is approximately one billion years older than the Sun. It is extremely chromospherically inactive, only slightly more active than Tau Ceti. The star is known to host one low-mass planet.
HD 109271 is a star in the constellation of Virgo. With an apparent magnitude of 8.05, it cannot be seen with the naked eye. Parallax measurements made by Gaia put the star at a distance of 182 light-years (56.0 parsecs) away. HD 109271 is a typical G-type main-sequence star.
QZ Puppis (QZ Pup, b Pup) is a class B2.5V (blue main-sequence) star in the constellation Puppis. Its apparent magnitude is 4.49 and it is approximately 650 light years away based on parallax. It is an ellipsoidal variable, ranging from 4.54 to 4.47 magnitude, with a reported period of 1.1 days.
HAT-P-21 is a G-type main-sequence star about 910 light-years away. The star has amount of metals similar to solar abundance. The survey in 2015 has failed to detect any stellar companions. The star is rotating rapidly, being spun up by the tides of giant planet on close orbit.
Tau Boötis, Latinized from τ Boötis, is an F-type main-sequence star approximately 51 light-years away in the constellation of Boötes. It is a binary star system, with the secondary star being a red dwarf. As of 1999, an extrasolar planet has been confirmed to be orbiting the primary star.
PDS 110 is a young star still approaching the main sequence. It has been classified as a T Tauri star, or as a pre-main sequence star. The emission lines indicative of a T Tauri classification are somewhat weaker than a typical T Tauri star, interpreted as a post-T Tauri stage.
The primary, component A, is a B-type main sequence star with a stellar classification of B9VspHgMn. It is a chemically peculiar star of the type called a mercury-manganese star. The star is tentatively cataloged as an Alpha2 Canum Venaticorum variable. The secondary, component B, was first separated via interferometry in 2004.
HD 127304 is a double star in the northern constellation of Boötes. The brighter component is a sixth magnitude A-type main sequence star with a stellar classification of A0Vs It has a faint magnitude 10.62 companion at an angular separation of 25.6″ along a position angle of 256° (as of 2013).
Antares appears as a single star when viewed with the naked eye, but it is actually a binary star, with its two components called α Scorpii A and α Scorpii B. The brighter of the pair is the red supergiant, while the fainter is a hot main sequence star of magnitude 5.5.
Harpaz, 1994, pp. 7–18 Star formation occurs in dense regions of dust and gas, known as giant molecular clouds. When destabilized, cloud fragments can collapse under the influence of gravity, to form a protostar. A sufficiently dense, and hot, core region will trigger nuclear fusion, thus creating a main-sequence star.
AD Leonis (Gliese 388) is a red dwarf star. It is located relatively near the Sun, at a distance of about 16 light years, in the constellation Leo. AD Leonis is a main sequence star with a spectral classification of M3.5V. It is a flare star that undergoes random increases in luminosity.
FU Tauri varies in brightness. The primary star is a T Tauri variable, a type of irregular pre-main-sequence star. Its brightness has been observed to vary from a photovisual magnitude of 16.0 to fainter than 17.0. Its photographic magnitude has been measured to vary between magnitude 15.1 and below magnitude 17.6.
The primary, component A, is an F-type main-sequence star with a stellar classification of F8V. It has 20% greater mass than the Sun and a 23% larger radius. Its age is about the same as the Sun and it is spinning with a projected rotational velocity of 5.4 km/s.
This ejected star, namely S5-HVS1, an A-type main-sequence star, notable as the fastest star detected as of November 2019, has been determined to be traveling at nearly four million miles an hour (more specifically, , almost 0.6% of the speed of light) away from the galactic core of the Milky Way.
Orbits of the 47 Ursae Majoris system planets. 47 UMa b is the innermost planet. 47 Ursae Majoris b orbits at a distance of 2.10 AU from its star, taking 1,078 days or 2.95 years to complete a revolution.It was the first long-period planet around a main sequence star to be discovered.
K2-28 is a metal rich M4-type main sequence star. One confirmed transiting exoplanet is known to orbit this star. There is another star 5.2 arcseconds to the north–east of K2-28 however this star has a different proper motion and is therefore physically unrelated and probably a background star.
A second companion, white-hued component Ab, has magnitude 6.97 and angular separation 0.2" from the primary in a 58-year orbit. This is a probably A-type main-sequence star with a class of A0V–A2V. The more distant component B is a type A1V star with magnitude 7.2 and separation 62.8".
This is a rapidly rotating Be star, showing an emission line spectrum on top of the normal absorption spectrum of the star, due to a circumstellar disk of ejected matter. It doesn't show any absorption lines from the disk. It is a B-type main-sequence star with a stellar classification of B9V.
Zeta Persei is the third-brightest star in the constellation at magnitude 2.86. Around 750 light-years from Earth, it is a blue-white supergiant 26–27 times the radius of the Sun and 47,000 times its luminosity. It is the brightest star (as seen from Earth) of a moving group of bright blue-white giant and supergiant stars, the Perseus OB2 Association or Zeta Persei Association. Zeta is a triple star system, with a companion blue- white main sequence star of spectral type B8 and apparent magnitude 9.16 around 3,900 AU distant from the primary, and a white main sequence star of magnitude 9.90 and spectral type A2, some 50,000 AU away, that may or may not be gravitationally bound to the other two.
The constellation Corona Borealis as it can be seen by the naked eye Alpha Coronae Borealis (officially named Alphecca by the IAU, but sometimes also known as Gemma) appears as a blue-white star of magnitude 2.2. In fact, it is an Algol-type eclipsing binary that varies by 0.1 magnitude with a period of 17.4 days. The primary is a white main-sequence star of spectral type A0V that is 2.91 times the mass of the Sun () and 57 times as luminous (), and is surrounded by a debris disk out to a radius of around 60 astronomical units (AU). The secondary companion is a yellow main-sequence star of spectral type G5V that is a little smaller (0.9 times) the diameter of the Sun.
Disc of debris around an F-type star An F-type main-sequence star (F V) is a main-sequence, hydrogen-fusing compact star of spectral type F and luminosity class V. These stars have from 1.0 to 1.4 times the mass of the Sun and surface temperatures between 6,000 and 7,600 K.Tables VII and VIII. This temperature range gives the F-type stars a yellow-white hue. Because a main- sequence star is referred to as a dwarf star, this class of star may also be termed a yellow-white dwarf (not to be confused with cooler white dwarfs). Famous examples include Procyon A, Gamma Virginis A and B,SIMBAD, entries on Gamma Virginis A, Gamma Virginis B, accessed June 19, 2007.
Antares B is a magnitude 5.5 blue-white main-sequence star of spectral type B2.5V; it also has numerous unusual spectral lines suggesting it has been polluted by matter ejected by Antares. It is assumed to be a relatively normal early-B main sequence star with a mass around , a temperature around , and a radius of about . Antares B is normally difficult to see in small telescopes due to glare from Antares, but can sometimes be seen in apertures over . It is often described as green, but this is probably either a contrast effect, or the result of the mixing of light from the two stars when they are seen together through a telescope and are too close to be completely resolved.
HD 76151 is a G-type main sequence star in the constellation of Hydra. It has an apparent visual magnitude of approximately 6.00. An infrared excess has been detected around this star, most likely indicating the presence of a circumstellar disk at a radius of 7.9 AU. The temperature of this dust is 99 K.
It is a candidate member of the TW Hydra stellar kinematic group. This is an F-type main-sequence star with a stellar classification of F5.5V. It is an estimated 1.13 billion years old and is spinning with a rotation period of 7.73 days. It shows evidence of a short-term activity cycle lasting days.
K2-229 (also designated EPIC 228801451 or TYC 4947-834-1) is a K-type main sequence star approximately 103 parsecs (335 light years) away in the constellation Virgo. It was observed by the Kepler Space Telescope during its K2 "Second Light" mission in Campaign 10, and has a system of three confirmed exoplanets.
Reprinted in 2012. Retrieved June 11, 2016. A star follows a pattern as it ages that depends on its mass at the beginning. Here, a chart depicting temperature and luminosity shows how a star 5 times the mass of our Sun changes from a main sequence star into a white dwarf and a planetary nebula.
The distance to this star, as determined from parallax measurements, is approximately 366 light years. It is drifting further away with a radial velocity of +1.3 km/s. This object is an A-type main-sequence star with a stellar classification of A1V. It is a suspected variable star of unknown type and magnitude.
The brighter star is a giant of spectral type K2III, while the companion is a main sequence star of spectral type B9.5V. Nu Canis Majoris is a yellow-hued giant star of magnitude 5.7, 278 light-years away; it is at the threshold of naked- eye visibility. It has a companion of magnitude 8.1.
All three components of δ Circini A are hot luminous stars. The brightest is an O8 star just beginning to evolve away from the main sequence. It is in a very close orbit with an O9.5 main sequence star. The two stars are deformed into ellipsoidal shapes and eclipse each other every 3.9 days.
HD 187123 has a planetary system with at least two planets in it. Artist's rendition of planets HD 187123b and c. HD 187123 is an 8th magnitude G-type main sequence star located approximately 150 light-years away in the constellation of Cygnus. Like our Sun, it is a yellow dwarf (spectral type G5V).
In 1932, HD 24479 was identified as a Be star by Olin C. Wilson at the Mount Wilson Observatory. In 1969, Cowley et al. listed a stellar classification of B9.5 V, matching a B-type main-sequence star. Slettebak (1982) gave it a class of B9 IV, suggesting this instead an evolving subgiant star.
The star HD 6434 is named Nenque. The name was selected in the NameExoWorlds campaign by Ecuador, during the 100th anniversary of the IAU. Nenque means the Sun in the language spoken by the Indigenous Waorani tribes. This object is a Sun-like G-type main-sequence star with a stellar classification of G2/G3V.
Radio emission was detected from this system in 1985/86. The supergiant primary is a slow irregular variable with an amplitude of about 0.1 magnitudes. Its close companion has 57% of the mass of the Sun. The secondary is a hot B-type main-sequence star, but still 2.5 magnitudes fainter than the primary.
HD 52265 is a 6th-magnitude G-type main sequence star located approximately 98 light-years away in the constellation of Monoceros. It is 21% more massive than and more than twice as luminous as the Sun. The age of the star is roughly 2.6 billion years. The star HD 52265 is named Citalá.
It is possible that the secondary is a pair of early A-type main-sequence stars. A more distant companion, ο Cassiopeiae B, lies 33.6 arcseconds away. It is an eleventh- magnitude, F-type main-sequence star. Because it has a similar proper motion to the central system, it is assumed to be gravitationally bound.
Iota Cassiopeiae is known to be a quintuple star system. The brightest star system, ι Cassiopeiae A, contains a white-colored A-type main-sequence star with a mean apparent magnitude of +4.61. The primary component is a tighter binary star system itself. The two stars themselves were resolved by adaptive optics, revealing two stars.
Initially thought to be a planet, it is now thought to be a brown dwarf around 22 times as massive as Jupiter. Iota and Psi Andromedae make up the asterism. Shining at magnitude 4.29, Iota Andromedae is a blue-white main sequence star of spectral type B8V around 500 light-years distant from Earth.
The magnitude 7.62 companion, component B, is a F-type main-sequence star with a class of F2V. It is radiating four times the luminosity of the Sun from its photosphere at an effective temperature of 6,806 K. The system is a source for X-ray emission, which is most likely coming from the secondary.
Each star is over a hundred thousand times the luminosity of the sun. LY Aur B is a single-lined spectroscopic binary with an orbital period of 20.5 days. It is probably an early B main sequence star and the companion is undetectable. The two stars combined are 47,000 times the luminosity of the sun.
The Sun is a main-sequence star, and thus generates its energy by nuclear fusion of hydrogen nuclei into helium. In its core, the Sun fuses 500 million metric tons of hydrogen each second. The nuclear binding energy curve. The formation of nuclei with masses up to iron-56 releases energy, as illustrated above.
Rho Herculis A is generally assigned a giant luminosity class, with Rho Herculis B most often considered to be a main sequence star. Rho Herculis A has been considered to be an Ap star, with unusually strong silicon or mercury and manganese absorption lines in its spectrum, but this is now considered to be dubious.
They have the spectrum of a B-type main sequence star with a stellar classification of B5 V. The luminosity has a micro-variability with a frequency of 0.94483 cycles per day and an amplitude of 0.0067 in magnitude. The third component is a magnitude 10 star at an angular separation of 0.51 arc seconds.
K2-32 is a G9-type main sequence star slightly smaller and less massive than the sun. Four confirmed transiting exoplanets are known to orbit this star. A study of atmospheric escape from the planet K2-32b caused by high-energy stellar irradiation indicates that the star has always been a very slow rotator.
Since a member of the system is a β Cephei-type variable star, the magnitude is not fixed but varies slightly between +4.70m and +4.74m. The period of this variability is 0.0889 days. The system is categorized as is a blue-white B-type main sequence star with a stellar classification of B3 V.
HD 171028 is a yellow main-sequence star in the constellation of Ophiuchus. The apparent magnitude is +8.31, visible in good binoculars. Unlike most planet-harboring stars, it does not have a Hipparcos number, though the distance was estimated at 90±7.8 parsecs. In the summer of 2007, a planet was discovered orbiting this star.
KOI-74 () is an eclipsing binary star in the constellation of Cygnus. The primary star is an A-type main-sequence star with a temperature of . It lies in the field of view of the Kepler Mission and was determined to have a companion object in orbit around it which is smaller and hotter than the main star.
The orbital period has been estimated at 0.439 days. The spectrum of this system matches a stellar classification of B3 Vnpe, which may indicate the primary is a B-type main sequence star. The 'e' suffix indicates the presence of emission lines, indicating this is a Be star. For Rho1 Arae, the emission lines are prominent and variable.
HD 93205 is a binary system of two large stars. The more massive member of the pair is an O3.5 main sequence star. The spectrum shows some ionised nitrogen and helium emission lines, indicating some mixing of fusion products to the surface and a strong stellar wind. The mass calculated from apsidal motion of the orbits is .
This is somewhat lower than expected from evolutionary modelling of a star with its observed parameters. The less massive member is an O8 main sequence star of approximately . It moves in its orbit at a speed of over and is considered to be a relativistic binary, which causes the apses of the orbit to change in a predictable way.
U Coronae Borealis (U CrB) is an Algol-type eclipsing binary star system in the constellation Corona Borealis. Its apparent magnitude varies between 7.66 and 8.79 over a period of 3.45 days The component stars are a blue-white main sequence star of spectral type B6V and a cooler yellow-white subgiant star of spectral type F8III-IV.
The pair orbit each other with a period of 105 years and an eccentricity of 0.39. Their semimajor axis has an angular size of and the orbital plane is inclined by 47°. The primary member, designated component A, has a magnitude of 5.02 and is an F-type main-sequence star with a stellar classification of F2V.
HD 104067 is an 8th magnitude K-type main sequence star located approximately 69 light years away in the constellation Corvus. This star is smaller, cooler, dimmer, and 80% as massive than our Sun. Also its metal content is seven- eighths as much as the Sun. In 2009, a gas giant planet was found in orbit around the star.
HD 125595 is a 9th magnitude K-type main sequence star located approximately 89 light years away in the constellation Centaurus. This star is smaller, cooler, dimmer, and less massive than our Sun. Also its metal content is 4% more than the Sun. In 2009, a gas giant planet was found in orbit around the star.
HD 90156 is a 7th magnitude G-type main sequence star located approximately 73 light years away in the constellation Hydra. This star is smaller, cooler, fainter, and less massive than our Sun. Also its metal content is over half as much as the Sun. In 2009, a gas giant planet was found in orbit around the star.
HIP 79431 is an 11th magnitude M-type main sequence star located approximately 47 light years away in the constellation Scorpius. This star is smaller, cooler, dimmer, and less massive than our Sun. Also its metal content is 2.5 times as much as the Sun. In 2010, a superjovian planet was found in orbit around the star.
Tau Ceti is noted for being the nearest Sun- like star at a distance of 11.9 light-years. It is a yellow-hued main-sequence star of magnitude 3.5. AA Ceti is a triple star system; the brightest member has a magnitude of 6.2. The primary and secondary are separated by 8.4 arcseconds at an angle of 304 degrees.
At that distance, the visual magnitude of this star is diminished by 0.15 from extinction due to interstellar dust. This is an A-type main-sequence star with a stellar classification of A0 V, per Houk (1979). However, Gray & Garrison (1987) have it classed as B9.5 III-n, suggesting it is a more evolved giant star.
Zeta Coronae Australis is a rapidly rotating main sequence star with an apparent magnitude of 4.8, 221.7 light years from Earth. The star has blurred lines in its hydrogen spectrum due to its rotation. Its spectral type is B9V. Theta Coronae Australis lies further to the west, a yellow giant of spectral type G8III and apparent magnitude 4.62.
This pair is a double-lined spectroscopic binary system that forms an Algol-like eclipsing binary. The brightness of the system decreases from 6.44 down to 6.53 during the primary eclipse. It has a stellar classification of A0V, which matches an A-type main-sequence star that is generating energy through hydrogen fusion at its core.
HD 205765 is a star in the equatorial constellation of Aquarius. It is an A-type main sequence star with an apparent magnitude of 6.2, which, according to the Bortle scale, makes it faintly visible to the naked eye from dark rural skies. This star is spinning rapidly with a projected rotational velocity of 172 km/s.
BD+14 4559, named Solaris, is a 10th magnitude K-type main sequence star located approximately 161 light years away in the constellation of Pegasus. On June 10, 2009, an exoplanet (Pirx) was found in orbit by Niedzielski et al. using the Hobby-Eberly Telescope. The star BD+14 4559 was named during the NameExoWorlds campaign by Poland.
The magnitude 7.76 star HD 2567 forms a common proper motion companion to this pair. The HD 2638 members have a projected separation of about and thus an orbital period of around 130 years. They have a combined stellar classification of K1V. The primary component is a G-type main-sequence star with a class of G8V.
Houk and Swift (1999) find a stellar classification of F0IV, matching an F-type subgiant star that has exhausted the hydrogen at its core and is evolving into a giant. Fox Machado et al. (2010) found a class of F0V, suggesting it is still a main sequence star. This is a pulsating variable star of the Delta Scuti type.
The star HD 4208 is named Cocibolca. The name was selected in the NameExoWorlds campaign by Nicaragua, during the 100th anniversary of the IAU. Cocibolca is the Nahuatl name for the Lake Nicaragua. This is a G-type main- sequence star with a stellar classification of , where the suffix notation indicates underabundances of iron and carbyne in the spectrum.
Gliese 638 is a main sequence star in the constellation of Hercules. It is located about 31.9 light years from the Earth. This is a suspected variable star with a measured apparent magnitude that ranges from 8.09-8.11. As a K-class star, it has a lower mass than the Sun, and consequently is less luminous.
The brighter member of this system has an apparent magnitude of 4.81. It is an A-type main sequence star with a stellar classification of A0 V. This star is spinning rapidly with a projected rotational velocity of 1 km/s. The fainter companion is a magnitude 7.43 star at an angular separation of 0.840 arcseconds.
It was made up of a small group of stars, now called 33 Arietis, 35 Arietis, 39 Arietis, and 41 Arietis, in the north of the constellation of Aries. The brightest star is now known as 41 Arietis (Bharani). At magnitude 3.63, it is a blue-white main sequence star of spectral type B8V around 166 light-years distant.
There is much uncertainty in the spectral type, with classifications ranging from a main sequence star to a giant. The spectra indicate the presence of a Be star in the system. According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, this star was titled as Nucatai.
It has an absolute magnitude of 0.56. This object is a solitary A-type main-sequence star with a stellar classification of A0Vn, a star that is currently fusing its core hydrogen. The 'n' suffix indicates "nebulous" absorption lines due to rapid rotation. It is around 181 million years old with a projected rotational velocity of 229 km/s.
Epsilon2 Arae (ε2 Arae, ε2 Ara) is the Bayer designation for a double star in the southern constellation of Ara. It is approximately distant from Earth. With an apparent visual magnitude of 5.3, it is faintly visible to the naked eye. The brighter star is a magnitude 5.44 F-type main sequence star with a stellar classification of .
The 6.06 magnitude companion star is a B-type main sequence star with a classification of B9 V. On average the two stars are separated by about 0.6 arcseconds and have an orbital period of roughly 554 years. Based upon their orbital elements, the system has a combined mass of around times the mass of the Sun.
The star drifting further away with a radial velocity of +18 km/s. It is a candidate member of the Lower Centaurus-Crux group of the Sco OB2 association. This object is a B-type main-sequence star with a stellar classification of B3V. A surface magnetic field has been detected with a strength on the order of .
Kepler-37b is an extrasolar planet (exoplanet) orbiting Kepler-37 in the constellation Lyra. it is the smallest planet discovered around a main- sequence star, with a radius slightly greater than that of the Moon. The measurements do not constrain its mass, but masses above a few times that of the Moon give unphysically high densities.
The primary component is a G-type giant. Its radius is about 13 times that of the Sun. The companion is likely a white- colored A-type main-sequence star that is fainter. The two stars are separated about 1.3 arcseconds away, and because of their large separation, the two stars take some 479 years to complete an orbit.
Theta Gruis, Latinized from θ Gruis, is a triple star system in the southern constellation of Grus. Its combined apparent visual magnitude is 4.28, which is bright enough to be seen with the naked eye. The system contains a magnetic Delta Delphini-like F5 star with a close fainter companion, plus a more distant G2 main sequence star.
ADS 1359 is a quadruple star system in the constellation Cassiopeia. It is composed of two sun like stars in an eclipsing binary with a 2.5-day period, which is in turn orbited by an A-type main-sequence star with a 185-year orbital period. There is also HD 236848 which is a distant proper motion companion.
55 It is located 5° WNW of delta Monocerotis and 2° SSE of 18 Monocerotis. The brightest star of the cluster is an orange G8 subgiant star of 8.0 magnitude, but it is possible that it is a foreground star. The cluster contains also blue giants. The brightest main sequence star is a B9 star with magnitude 9.1.
The star HD 224693 is named Axólotl. The name was selected in the NameExoWorlds campaign by Mexico, during the 100th anniversary of the IAU. Axólotl means water animal in the native Nahuatl language, which is an amphibious species from the basin of Mexico. This is an ordinary G-type main-sequence star with a stellar classification of G2V.
Planet HD 125612 b HD 125612 b is an extrasolar planet which orbits the G-type main sequence star HD 125612, located approximately 188 light years away in the constellation Virgo. This planet was detected using the doppler spectroscopy method and the discovery was first announced in a paper submitted to the arXiv preprint repository on April 10, 2007.
Gamma2 Fornacis (γ2 For) is a star in the constellation Fornax, with an apparent magnitude of 5.4. It is an A1 main sequence star 2.4 times as massive as the Sun and 120 times as luminous. Gamma1 Fornacis is a 6th magnitude star four degrees to the north. γ2 Fornacis is about from Earth and is receding at .
Component C lies at an angular separation of 22.6 arc seconds from the AB pair, and may be a common proper motion companion. It is an A-type main sequence star with a classification of A2 V. A fourth component at an angular separation of 6.15 arc seconds from component A, may be a brown dwarf.
This is a B-type main-sequence star with a stellar classification of B9V. It has a high rate of spin, showing a projected rotational velocity of 116 km/s. The star has 2.7 times the mass of the Sun and is radiating 73 times the Sun's luminosity from its photosphere at an effective temperature of about 10,641 K.
Qatar-2 is a K-type main-sequence star about 595 light-years away. The star is much older than Sun, and has a concentration of heavy elements similar to solar abundance. The star features a numerous and long-lived starspots, and belongs to a peculiar variety of inflated K-dwarfs with strong magnetic activity inhibiting internal convection.
It has a mass of about 1.2 times the mass of the Sun, and 2.6 times the Sun's radius. The magnitude difference between the two components is estimated to be . The estimated properties of the secondary indicate that it is most likely a K-type main sequence star. The system displays no indication of chromospheric activity.
V830 Tauri is an M-type star. The star has a mass of roughly 1 solar mass, but has a radius of 2 solar radii, due to the star's age, which means that it hasn't fully contracted yet to become a main-sequence star. It has a surface temperature of . For comparison, the Sun's surface temperature is .
An O-type main-sequence star (O V) is a main-sequence (core hydrogen-burning) star of spectral type O and luminosity class V. These stars have between 15 and 90 times the mass of the Sun and surface temperatures between 30,000 and 50,000 K. They are between 40,000 and 1,000,000 times as luminous as the Sun.
Kepler-160 is a main-sequence star located in the constellation Lyra in the field of view of the Kepler Mission, a NASA-led operation tasked with discovering terrestrial planets. The star, which is very similar to the Sun in mass and radius, has two confirmed, one unconfirmed and at least one suspected planets orbiting it.
CoRoT-7c is an extrasolar planet which orbits the G-type main sequence star CoRoT-7, located approximately 489 light years away in the constellation Monoceros. It's either a super-Earth or a Neptune-like planet, orbiting at 0.046 AU from the star, taking 3.7 days or 89 hours to make one round trip around the star.
The brighter component, Nu Scorpii Aa, has a spectral type of B3V implying a B-type main sequence star. The fainter component, Nu Scorpii Ab, is thought to have an apparent magnitude of 6.90. Nu Scorpii Ac is the third component of the Nu Scorpii A subsystem. 63 milliarcseconds away, it has an apparent magnitude of 6.62.
The outer member, component C, has an orbital period of around half a million years. As of 2007, it had an angular separation of 115.8 arc seconds along a position angle of 248° from the primary. It is an F-type main sequence star with a classification of F5 V and an estimated 1.29 times the Sun's mass.
This is a G-type main-sequence star with a stellar classification of G1V. It is a solar-type star with slightly higher mass and radius compared to the Sun. The metallicity is higher than solar. It is an estimated 3.8 billion years old and is spinning with a projected rotational velocity of 6 km/s.
Their combined stellar classification is F4V, matching that of an F-type main sequence star. They have an angular separation of 0.300″ along a position angle of 129.0° (as of 2014). The pair orbit each other with an estimated period of 40.657 years. No significant level of chromospheric activity has been detected coming from either star.
49 Cancri is classified from its spectrum as an Ap star, with enhanced lines of silicon, europium, and chromium. Additionally, calcium and magnesium lines are described as weaker than normal. 49 Cancri is classified as an A1 main sequence star. It has three times the mass of the Sun, an effective temperature of , and a radius of .
It may be a member of the Wolf 630 moving group of stars. This object has a stellar classification of G7 V, which would suggest it is a G-type main-sequence star. However, Jofré et al. (2015) consider it to be a more evolved subgiant star due to a surface gravity of log g = 3.87.
18 scorpii is on the northern boundary of the constellation. Its high proper motion positions it in Ophiuchus before 1700. 18 Scorpii is a main sequence star of spectral and luminosity type G2 Va, with the luminosity class of 'V' indicating it is generating energy through the nuclear fusion of hydrogen in its core region. Sousa et al.
Gliese 179 is a 12th magnitude M-type main sequence star located approximately 40 light years away in the constellation Orion. This star is smaller, cooler, fainter, and less massive than our Sun. Also its metal content is twice as much as the Sun. In 2009, a gas giant planet was found in orbit around the star.
The primary member, component A, is a yellow-white hued F-type main sequence star with a stellar classification of F6 V. It is around 2.6 billion years old and a member of the thin disk population. The primary has about 1.66 times the mass of the Sun while the secondary is just 0.33 times the Sun's mass.
Zeta Tucanae (ζ Tuc, ζ Tucanae) is a star in the constellation Tucana. It is a spectral class F9.5 main sequence star with an apparent magnitude of +4.23. Despite having a slightly lower mass, this star is more luminous than the Sun. Based upon parallax measurements by the Hipparcos spacecraft, it is approximately 28.0 light years from Earth.
HD 146389 (also known as WASP-38), is the yellow-white main sequence star in the constellation of Hercules. The star was given the formal name Irena by the International Astronomical Union in January 2020.The IAU announces names for WASP exoplanets The star is known to host one exoplanet, designated WASP-38b or formally named 'Iztok'.
V Cephei is a white main sequence star in the constellation Cepheus. It only varies slightly by 0.03 of a magnitude. It was suspected of being variable by American astronomer Seth Carlo Chandler noting in 1890 that it varied by 0.7 magnitude but that it needed more confirmation. Subsequent observers were divided in whether they noted variability or not.
The spectrum of the star matches a stellar classification of , indicating it is an ordinary K-type main-sequence star that is generating energy through hydrogen fusion at its core. It is radiating 29% of the Sun's luminosity from its photosphere at an effective temperature of 4,822 K. The star has 66% of the Sun's radius.
HD 44219 is an 8th magnitude G-type main sequence star located approximately 164 light years away in the constellation Monoceros. This star is larger, cooler, brighter, and about the same mass as our Sun. Also its metal content is one-fifteenth more than the Sun. In 2009, a gas giant planet was found in orbit around the star.
HD 156411 is a 7th magnitude G-type main sequence star located approximately 179 light years away in the constellation Ara. This star is larger, hotter, brighter, and more massive than our Sun. Also its metal content is three- fourths as much as the Sun. In 2009, a gas giant planet was found in orbit around the star.
14 Herculis or 14 Her is the Flamsteed designation of a K-type main-sequence star approximately 58.5 light-years away in the constellation Hercules. Because of its apparent magnitude, the star cannot be seen with the naked eye. As of 2006, it is thought that 14 Herculis has two extrasolar planets in orbit around the star.
HD 181720 is an 8th magnitude G-type main sequence star located approximately 190 light years away in the constellation Sagittarius. This star is larger, hotter, brighter, and less massive than our Sun. Also its metal content is three-tenths as much as the Sun. In 2009, a gas giant planet was found in orbit around the star.
HD 190984 is a 9th magnitude F-type main sequence star located approximately 330 light years away in the constellation Pavo. This star is larger, hotter, brighter, and more massive than our Sun. Also its metal content is one-thirds as much as the Sun. In 2009, a gas giant planet was found in orbit around the star.
HD 28254 is an 8th magnitude G-type main sequence star located approximately 178 light years away in the constellation Dorado. This star is larger, cooler, brighter, and more massive than our Sun. Also its metal content is 2.3 times as much as the Sun. In 2009, a gas giant planet was found in orbit around the star.
HD 215497 b is an extrasolar planet which orbits the K-type main sequence star HD 215497, located approximately 142 light years away in the constellation Tucana. This planet has at least 6.6 times the mass of Earth. This planet was detected by HARPS on October 19, 2009, together with 29 other planets, including HD 215497 c.
HD 103197 is a 9th magnitude K-type main sequence star located approximately 170 light years away in the constellation Centaurus. The star is smaller, cooler, dimmer, and less massive than our Sun. Its metal content is thirteen- eighths as much as the Sun. In 2009, a gas giant planet was found in orbit around the star.
It has an orbital period of 2.65 years and an eccentricity of 0.23. The semimajor axis is 0.11 AU, or 11% of the distance between the Sun and the Earth, and the orbital plane is inclined at an angle of 24.2°.The primary member, component A, is an F-type main sequence star with a stellar classification of F2 V. The spectrum of the secondary, component B, can not be readily separated from that of the primary, so its type can only be estimated as a main sequence star lying in the range between F7 V and G4 V. The system is estimated to be 1.8 billion years old, with the primary having 1.4 times the mass of the Sun and the secondary being about equal to the Sun's mass.
GD 61 is a white dwarf with a planetary system located 150 light-years from Earth in the constellation Perseus. It is thought to have been a main-sequence star of spectral type A0V with around three times the mass of the Sun that has aged and passed through a red-giant phase, leaving a dense, hot remnant that has around 70% of the Sun's mass and a surface temperature of 17,280 K. It is thought to be around 600 million years old, including both its life as a main- sequence star and as a white dwarf. It has an apparent magnitude of 14.8. GD 61 was first noted as a potential degenerate star in 1965, in a survey of white-dwarf suspects by astronomers from the Lowell Observatory in Arizona.
The pair consist of an A-type giant and a less evolved A-type main-sequence star with stellar classifications of A9 III + A3 V, respectively. These in turn share an orbit with the primary, component A, having a period of 20 years and an eccentricity of 0.51. The last is an orange-hued K-type giant with a class of K2 III.
The star has 2.5 times the mass of the Sun and has expanded to more than 8 times the Sun's radius. It is radiating about 48 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 5,032 K. The secondary is most likely a low mass main sequence star with no more than 0.4 times the mass of the Sun.
The brighter component is an A-type main-sequence star with a stellar classification of A0Va. It may form a binary system of two roughly equal stars. An infrared excess suggests there is a debris disk orbiting from the star with a mean temperature of 95 K. It has one visual companion at an angular separation of about and magnitude 13.7.
KOI-81 is an eclipsing binary star in the constellation of Cygnus. The primary star is a late B-type or early A-type main-sequence star with a temperature of . It lies in the field of view of the Kepler Mission and was determined to have an object in orbit around it which is smaller and hotter than the main star.
It has an absolute magnitude of −2.3. The primary is an orange-hued K5II-type star (K-type bright giant) and the secondary is a smaller blue star similar to Regulus; its period is 972 days. The secondary is a B7V-type star, a B-type main-sequence star. Zeta Aurigae's maximum magnitude is 3.7 and its minimum magnitude is 4.0.
Of magnitude 4.05, nearby Iota Persei has been considered a member of the group, but is actually located a mere 34 light-years distant. This star is very similar to our Sun, shining with 2.2 times its luminosity. It is a yellow main sequence star of spectral type G0V. Extensive searches have failed to find evidence of it having a planetary system.
According to Eggen (1998), this is a member of the Hyades Supercluster. This is an A-type main-sequence star with a stellar classification of A6 V. Cowley et al. (1969) classified it as a Delta Delphini star, which is a type of suspected Am star. The star is around 394 million years old with a projected rotational velocity of 73 km/s.
V957 Scorpii shows a peculiar B5 or B6 spectrum. Its luminosity class has been given as main sequence (V), subgiant (IV), giant (III), and supergiant (Ib). From its position in the H-R diagram, it is actually thought to be a main sequence star. With a helium abundance 25 times lower than that of the sun, it is classified as helium-weak.
HD 115404 is a binary star system located in the constellation Coma Berenices. Parallax measurements made by Hipparcos put the system at 36 light-years, or 11 parsecs, away. The combined apparent magnitude of the system is 6.52, with the magnitudes of the components being 6.66 and 9.50. The primary component, designated A, is a K-type main sequence star.
The total brightness change is only 0.15 magnitudes. The third component is a B0.5 main sequence star in a long eccentric orbit around the close pair. It is fainter and cooler than either of the two close stars, yet it is calculated to be more massive than δ Cir A, so it is suspected that it may also be a close binary system.
The primary, component A, is a yellow-white hued bright giant with a stellar classification of F8 II, and it is a classical Cepheid variable. The combined apparent magnitude of the system ranges from 5.69 to 6.19 over 5.273 days. The secondary companion, component B, is a main sequence star with a class of B6 V and an absolute magnitude of about −0.12.
It is radiating 1,698 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 5,173 K. The secondary, component B, appears to be a B-type main-sequence star with a stellar classification of B7V. It is a suspected binary of unknown period with component masses of 3.3 and 1.2 times the mass of the Sun.
HAT-P-20 is a K-type main-sequence star about 232 light-years away. The star has a strong starspot activity, and its equatorial plane is misaligned by 36° with the planetary orbit. Although star with a giant planet on close orbit is expected to be spun-up by tidal forces, only weak indications of tidal spin-up were detected.
HD 208487 is a 7th magnitude G-type main sequence star located approximately 144 light-years away in the constellation of Grus. It has the same spectral type as our sun, G2V. However, it is probably slightly less massive and more luminous, indicating that it is slightly older. As of 2008, there is one known extrasolar planet confirmed to be orbiting the star.
HD 63454, now known as "Ceibo" is a ninth magnitude K-type main sequence star located approximately 117 light-years away in the constellation of Chamaeleon. It is somewhat cooler and less luminous than our Sun. To see the star one needs a small telescope. It is located near the south celestial pole and is never visible north of latitude 12°N.
NV Puppis (NV Pup), also known as υ1 Puppis, is a class B2V (blue main- sequence) star in the constellation Puppis. Its apparent magnitude is 4.67 and it is approximately 800 light years away based on parallax. It is a γ Cas variable, ranging from 4.78 to 4.58 magnitude. It is most likely an optical double with the nearby NW Puppis.
HD 17925 (32 G. Eridani) is a solitary K-type main sequence star located 34 light-years away, in the constellation Eridanus. It is a likely member of the Local Association of nearby, co-moving stars. The spectrum shows a strong abundance of lithium, indicating that it is young star. This likely makes its point of origin the nearby Scorpio–Centaurus Complex.
GSC 03089-00929 is a magnitude 12 star located approximately 760 light-years away in the constellation of Hercules. This star is a G type main sequence star that is similar to but slightly cooler than our sun. This star is identified in SIMBAD as a variable star per the 1SWASP survey. The star GSC 03089-00929 is named Pipoltr.
Its companion, 6th magnitude GJ 822.1 B, is a yellow main sequence star of the spectral type G0V. It is similar to the Sun in size, surface temperature, and luminosity. Tau Cygni is classified as a δ Scuti variable. The magnitude range is given as 3.65 to 3.75, which is the combined magnitude for both components, although the variable component is A.
The primary, Lambda Cancri A, is a B-type main-sequence star with a stellar classification of B9.5 V. It has 2.1 times the mass of the Sun and radiates 78 times the Sun's luminosity from its photosphere at an effective temperature of roughly 9,500 K. Its close companion, Lambda Cancri B, has 80% of the mass of the Sun.
The system made its closest approach about 150,000 years ago when it came within . The primary member of this system is a G-type main-sequence star with a stellar classification of . It has 12% more mass and a 25% larger radius than the Sun. The star is about seven billion years old and is spinning with a rotation period of 10.6 days.
This star is 21% more massive than the Sun and has a radius 2.5 times the Sun's. It is radiating 8.7 times the luminosity of the Sun from its outer atmosphere at an effective temperature of 6,290 K. This temperature is what gives it the yellow-white hue of an F-type main sequence star with a stellar classification of F9 V.
The primary, component A, is a G-type main-sequence star with a stellar classification of G5V, indicating it is generating energy through core hydrogen fusion. Estimates of the star's age range from five to almost nine billion years. It has 1.10 times the mass of the Sun and 1.24 times the Sun's radius. The star has a higher than solar metallicity.
The star has an absolute magnitude of −1.20. The Bright Star Catalogue assigns this star a stellar classification of A2V, suggesting this is an A-type main-sequence star. However, Houk and Swift (1999) found a more evolved subgiant class of A0IV. It has around 2.4 times the mass of the Sun and is an estimated 405 million years old.
It has a projected rotational velocity of 255 km/s, resulting in an equatorial bulge with a radius 13% larger than the polar radius. It has a magnitude 9.5 companion G-type main sequence star that may form a binary star system with Delta Arae. There is a 12th magnitude optical companion located 47.4 arcseconds away along a position angle of 313°.
CoRoT-3 is a white-yellow dwarf main sequence star hotter than our Sun. This star is located approximately 2560 light-years away in the constellation of Aquila. The apparent magnitude of this star is 13, which means it is not visible to the naked eye but can be seen with a medium-sized amateur telescope on a clear dark night.
It is drifting further away with a radial velocity of +27 km/s. The magnitude 4.87 primary, designated component A, is a B-type main-sequence star with a stellar classification of B2V. During a search for Beta Cephei variables in the southern sky, it was initially classed as a very short period variable. However, this variability was not confirmed by subsequent observations.
K2-141 is an orange main sequence star about 61 parsecs away in K2 Campaign 12, within the constellation Aquarius. It has a radius of 0.681 and a mass of 0.708 . It has a temperature of 4599 K and is between 1.6 and 12.9 billion years old. For comparison, the Sun has a temperature of 5778 K and is 4.5 billion years old.
This is a B-type main-sequence star with a stellar classification of B9 V. It is spinning rapidly, showing a projected rotational velocity of 335. The star has an estimated 2.77 times the mass of the Sun and about 3.1 times the Sun's radius. It is radiating 75 times the Sun's luminosity from its photosphere at an effective temperature of 10,789 K.
Phi1 Hydrae is an ordinary G-type main-sequence star, having a Sun- like stellar classification of G2 V and a photospheric temperature only slightly higher than the sun. However, the mass is 34% greater than the Sun, and it is radiating 4.4 times the Sun's luminosity. Phi1 Hydrae is moving further from the Sun with a radial velocity of +15.8 km/s.
The primary, designated component A, has a stellar classification of B9III, matching a blue giant. The magnitude 8.34 secondary, component B, is an A-type main-sequence star of class A7V. A third star of 10th magnitude, BD+77 763, is listed as component C in the Washington Double Star Catalog although it is a background object unrelated to the other two.
Omicron Cephei, Latinized from ο Cephei, is a binary star in the constellation of Cepheus. It consists of a less massive F-type main sequence star in orbit with a more massive G-type giant star. The overall apparent visual magnitude of the system is 4.75. The pair was first determined to be binary by F. G. W. Struve in 1832.
This object is an A-type main-sequence star with a stellar classification of A0V. It is 94 million years old with a high rotation rate, showing a projected rotational velocity of 149. The star has 2.46 times the mass of the Sun and is radiating 49 times the Sun's luminosity from its photosphere at an effective temperature of 10,325 K.
HD 147018 is a G-type main sequence star in the constellation of Triangulum Australe. It has an apparent visual magnitude of approximately 8.4. In August 2009, two extrasolar planets, HD 147018 b and HD 147018 c, were reported to be orbiting this star. The planets were found using the radial velocity method, using the CORALIE spectrograph at La Silla Observatory, Chile.
Accessed on line November 25, 2008. In 2006 and 2007, J. D. Monnier and his coworkers produced an image of Altair's surface from 2006 infrared observations made with the MIRC instrument on the CHARA array interferometer; this was the first time the surface of any main- sequence star, apart from the Sun, had been imaged. The false-color image was published in 2007.
XO-5 is a yellow dwarf main sequence star located approximately 910 light- years away from Earth in the Lynx constellation. It has a magnitude of about 12 and cannot be seen with the naked eye but is visible through a small telescope. XO-5 have a suspected red dwarf companion with a temperature 3500 K, on a wide orbit.
Upsilon Orionis (υ Ori, υ Orionis) is a star in the constellation Orion. It has the traditional name Thabit or Tabit (ﺛﺎﺑﺖ, Arabic for "the endurer"), a name shared with pi3 Orionis. It is a blue-white main sequence star of apparent magnitude 4.62 located over 3000 light-years distant from the Solar System. It is a suspected Beta Cephei variable.
The planet orbits an A-type main sequence star named Beta Pictoris. The star has a mass of 1.75 solar masses () and a radius of 1.8 solar radii (). It has a surface temperature of 8056 K and is only 12 million years old. It is slightly metal-rich, with a metallicity (Fe/H) of 0.06, or 112% of that found in the Sun.
The orange main-sequence star is the primary of magnitude 4.4, and the white secondary of magnitude 9.5 is the most easily visible white dwarf. The red dwarf, of magnitude 11, orbits the white dwarf every 250 years. The 40 Eridani system is 16 light-years from Earth. p Eridani is a binary star with two orange components, 27 light-years from Earth.
This is a B-type main sequence star with a stellar classification of B8.5V. The star is about 107 million years old and is spinning rapidly with a projected rotational velocity of 277 km/s. It has an infrared excess, which suggests a debris disk is orbiting the star at a radius of with a mean temperature of 90 K.
GJ 9827 is a star in the constellation of Pisces. It is a K-type main-sequence star with an apparent magnitude of 10.250. It is 97 light-years (30 parsecs) away, based on parallax. The rotation period of the star cannot be determined as in 2020, and can be either around 15 or 30 days, depending on interpretation of available data.
HD 99922 is a double star system in the constellation of Crater. It shines with an apparent visual magnitude of 5.77 from a distance of about 450 light years (140 parsecs) away from the Earth. The primary star is an A-type main sequence star; the secondary star is located about 8 arcseconds away. Other designations include HR 4428 and HIP 56078.
The two stars orbit each other every 5.5226013 days. Their orbit is fairly eccentric, at 0.0844. The combined spectrum of 66 Eridani matches that of a B-type main-sequence star, and the two stars have similar masses. The spectrum also shows excess of mercury and manganese, as it is a type of chemically peculiar star called a mercury-manganese star.
Eta Crateris is an ordinary A-type main sequence star with a stellar classification of A0 V. It is about 2.7 times the radius of the Sun and radiates 48.5 times the solar luminosity from its outer atmosphere at an effective temperature of 9,687 K. It 350 million years old and is spinning with a projected rotational velocity of 65 km/s.
OGLE-2005-BLG-169L is a dim and distant magnitude 20 galactic bulge star located about 2,700 parsecs away in the constellation Sagittarius. If it is a main sequence star, then it is most likely a red dwarf with about half of the mass of the Sun. Other possibilities are a white dwarf star, or (less likely) a neutron star or black hole.
This is a B-type main-sequence star with a stellar classification of B4 V. The star is roughly 40 million years old, and is spinning with a projected rotational velocity of 102 km/s. It has about 5.7 times the mass of the Sun and is radiating 560 times the Sun's luminosity at an effective temperature of 16,300 K.
The primary, designated component A, is an A-type main-sequence star with a stellar classification of A8 Vn. The 'n' notation indicates "nebulous" lines due to rapid rotation. It is a shell star, with weak shell lines of singly-ionized titanium being detected in the near ultraviolet in 1970. These may have come from a sporadic mass loss event.
The visible component of this system is an ordinary A-type main-sequence star with a stellar classification of A9 V, which indicates it is generating energy by hydrogen fusion at its core. It has 2.4 times the mass of the Sun and is radiating 60 times the Sun's luminosity from its photosphere at an effective temperature of 7,907 K.
It is moving further from the Earth with a heliocentric radial velocity of +37 km/s. Based upon a stellar classification of F6 V, the brighter component is an F-type main-sequence star that is generating energy through hydrogen fusion at its core. Cowley (1976) listed a class of F5 IIIm?, which suggests it may be an Am star.
The two may be an optical double or a true multiple star system, with a separation of at least 50,000 astronomical units and the stars taking 3.5 million years to orbit each other. HR 4691 is itself double, composed of an ageing yellow- orange giant whose spectral type has been calculated at K0 or G3, and an F-type main sequence star.
HD 34445 is a 7th-magnitude G-type main-sequence star located in the constellation Orion. Parallax measurements made by Gaia put the star at about 150.5 light-years (46.15 parsecs) away. At an age of 8.5 billion years, this star is larger, hotter, brighter, and more massive than our Sun. Also its metal content is roughly 40% greater than the Sun.
At that time, the star will become the brightest in the night sky, potentially reaching magnitude −0.88. The magnitude 5.66 primary component is an F-type main-sequence star with a stellar classification of F2V. It is a Delta Scuti variable that varies by a few hundredths of a magnitude over roughly 16 hours. The star is an estimated 1.5 billion years old.
The abundance of elements more massive than helium is 71% of the Sun's and it has a relatively high projected rotational velocity of 32 km/s. This star is estimated to be less than half the age of the Sun, at 2.1 billion years. The secondary component, 84 Ceti B, has a classification of K2V, making it a K-type main sequence star.
Rho is an orange giant of spectral type K3III located around 160 light-years from Earth. It is ever so slightly variable, wavering by 0.003 of a magnitude from its average of 3.57. Sigma, a yellow-white main sequence star of spectral type F3V, is suspected of varying in brightness from 4.45 to 4.49. It is around 52 light-years distant.
German astronomer Johann Elert Bode depicted it as the pendulum of the clock, while Lacaille made it one of the weights. It is an orange giant star of spectral type K2III that has swollen to around 11 times the diameter of the Sun, having spent much of its life as a white main-sequence star. At an estimated 1.55 times the mass of the Sun, it is radiating 38 times the Sun's luminosity from its photosphere at an effective (surface) temperature of 5,028K. At magnitude 4.93, Delta Horologii is the second-brightest star in the constellation, and forms a wide optical double with Alpha. Delta itself is a true binary system composed of a white main sequence star of spectral type A5V that is 1.41 times as massive as the Sun with a magnitude of 5.15 and its fainter companion of magnitude 7.29.
HR 297 is a solitary star in the northern circumpolar constellation of Cassiopeia. It has an apparent visual magnitude of 5.8, making it faintly visible to the naked eye from dark suburban skies. Parallax measurements with the Hipparcos spacecraft put this system at a distance of roughly 263 light years. This is an F-type main sequence star with a stellar classification of F7V.
The star is radiating 324 times the luminosity of the Sun from its photosphere at an effective temperature of 11,960 K. The companion, Beta1 Sagittarii B, is a magnitude 7.4 A-type main sequence star with a class of A5 V. It has 1.89 times the radius of the Sun and may be spinning faster than the primary with a projected rotational velocity of 140 km/s.
Groombridge 1618 is a star in the northern constellation Ursa Major. With an apparent visual magnitude of +6.6, it lies at or below the threshold of stars visible to the naked eye for an average observer. It is relatively close to Earth, at 15.88 light years. This is a main sequence star of spectral type K7.5 Ve, having just 67% of the Sun's mass.
In 1998, the Extreme Ultraviolet Explorer space telescope detected a strong flare that released an X-ray emission nearly equal to the output of the entire star. The quiescent X-ray luminosity of Mu Velorum A is about . The fainter companion, Mu Velorum B, is a main sequence star with an apparent magnitude of 6.4 and an assigned stellar classification of G2V. However, this classification is suspect.
The mass of GD 356 is whereas when it was a main sequence star it would have had a mass of . In order to reach a temperature of 7510 K it would have become a white dwarf about 1.6 Gya. Prior to this the main sequence lifetime would have been 500 million years giving it a total age of 2.1 billion years. The current magnitude is 15.
The parent star K2-38 is a G2 main-sequence star, similar to our own Sun. It is 1.10 and 1.07 , with a temperature of 5757 K and an unknown age. For comparison, the Sun has a temperature of 5778 K and is about 4.5 billion years old. The visual magnitude of K2-38, or how bright it appears to the human eye, is 11.39.
Rho1 Arietis is the Bayer designation for a star in the northern constellation of Aries, the ram. It has an apparent visual magnitude of 7.01, making it a challenge to see with the naked eye even under ideal dark-sky conditions. Based upon an annual parallax shift measurement of 12.07 mas, it is distant from the Earth. It is a white-hued A5 main sequence star.
HIP 70849 is a 10th magnitude K-type main sequence star located approximately 78 light years away in the constellation Lupus. This star, which resembles a brighter red dwarf, is smaller, cooler, dimmer, and less massive than our Sun. In 2009, a gas giant planet/brown dwarf was found in orbit around it. There is also a potential T4.5 brown dwarf companion orbiting ~9000AU from HIP 70849.
Alpha Lacertae is a blue-white hued main-sequence star of magnitude 3.8, 102 light-years from Earth. It has a spectral type of A1 V and is an optical double star. Beta Lacertae is far dimmer, a yellow giant of magnitude 4.4, 170 light-years from Earth. Roe 47 is a multiple star consisting of five components (magnitudes 5.8, 9.8, 10.1, 9.4, 9.8).
Three star systems have been discovered to have exoplanets. HD 111232 is a yellow main-sequence star around 78% as massive as the Sun around 95 light-years distant. It has a planet (HD 111232 b) around 6.8 times the mass of Jupiter that has an orbital period around 1143 days. HD 112410 is a yellow giant of spectral type G8III located around 439 light-years distant.
Like the star Vega, it has excess infrared radiation, which indicates it may be ringed by a disk of dust. It is currently a main-sequence star, but will eventually evolve into a white dwarf; currently, it has a luminosity 31 times greater, and a radius and mass of 2.3 times that of the Sun. Beta Coronae Australis is an orange giant 474 light years from Earth.
Delta Chamaeleontis forms the southernmost component of the constellation's "dipper" or bowl. Together with Gamma Chamaeleontis, they point to a spot that is within 2° of the south celestial pole. This is a B-type main sequence star with a stellar classification of B3 V. However, Hiltner et al. (1969) give a classification of B2.5 IV, which would suggest it is a more evolved subgiant star.
The brighter component is an A-type main sequence star with a stellar classification of A1 Vnn. It is spinning rapidly with a projected rotational velocity of 285 km/s. This is giving the star an oblate shape with an equatorial bulge that is 20% larger than the polar radius. It has an estimated 2.88 times the mass of the Sun and 2.7 times the Sun's radius.
Yellow supergiants cooling for the first time may be massive stars of up to or more, but post-red supergiant stars will have lost around half their initial mass. Chemically, most yellow hypergiants show strong surface enhancement of nitrogen and also of sodium and some other heavy elements. Carbon and oxygen are depleted, while helium is enhanced, as expected for a post-main-sequence star.
Chini et al. (2012) identified this as a single-lined spectroscopic binary system. The visible component is a B-type main-sequence star with a stellar classification of B8 V. It is about 17 million tears old and is spinning rapidly with a projected rotational velocity of 251 km/s. The star has 3.6 times the mass of the Sun and 3.05 times the Sun's radius.
HD 217786 is a binary star about away. The primary main-sequence star belongs to the spectral class of F8. It is much older than Sun and is depleted of heavy elements, having 65% of solar abundance. The red dwarf stellar companion at a projected separation of 155 AU was discovered in 2016, and no other companion stars were detected at separations from 2.74 to 76.80 AUs.
Upsilon Cygni, Latinized from υ Cygni, is a star in the northern constellation of Cygnus. It is visible to the naked eye, having an apparent visual magnitude of 4.43. Based upon an annual parallax shift of 5.08 mas, it lies at a distance of roughly 640 light years from the Sun. This is a B-type main sequence star with a stellar classification of B2 Vne.
Tau Pegasi belongs to spectral class A5 Vp, making it an A-type main-sequence star. This is a Delta Scuti variable star with a pulsation period of 0.94 hours. It is rotating rapidly with a projected rotational velocity of 150 km s−1. Tau Pegasi is radiating nearly 30 times the luminosity of the Sun from its outer atmosphere at an effective temperature of 7,762 K.
It has a stellar classification of A1V, suggesting the primary component is an A-type main- sequence star. The star is about 400 million years old with a moderate rotation rate, showing a projected rotational velocity of 52 km/s. It has 2.6 times the mass of the Sun and is radiating 74 times the Sun's luminosity from its photosphere at an effective temperature of 9,683 K.
The primary component is a G-type bright giant. It is over five times as massive as the Sun, and over 77 times as wide. Its companion is a B-type main-sequence star, 3.4 times as massive as the Sun. The stars have an orbit that are oriented in such a way that they periodically eclipse each other, blocking the other star's light.
The visible component is an A-type main sequence star with a stellar classification of A1 V. It has 3.25 times the mass of the Sun and about twice the Sun's radius. The projected rotational velocity is relatively low at 23 km/s. The star is radiating 214 times the luminosity of the Sun from its photosphere at an effective temperature of 9,908 K.
In this case, light from both stars can be detected and it is a double-lined spectroscopic binary. The two have an orbital period of 28.28 days and a fairly high eccentricity of 0.56. The primary star is an A-type main-sequence star and shows unusual absorption lines in its spectrum, so it is an Am star with an effective temperature of 7,838 K.
Kepler-32 is an M-type main sequence star located about 1070 light years from Earth, in the constellation of Cygnus. Discovered in January 2012 by the Kepler spacecraft, it shows a 0.58 ± 0.05 solar mass (), a 0.53 ± 0.04 solar radius (), and temperature of 3900.0 K, making it half the mass and radius of the Sun, two-thirds its temperature and 5% its luminosity.
NGC 1977. (Mount Lemmon SkyCenter Schulman Telescope courtesy Adam Block 42 Orionis is a class B1V (blue main-sequence) star in the constellation Orion. Its apparent magnitude is 4.59 and it is approximately 900 light years away based on parallax. The primary star, Aa, has one spectroscopic companion Ab of magnitude 6.3 and separation 0.16", and a more distant companion B of 7.5 magnitude at 1.6" separation.
Nu Phoenicis is a F-type main-sequence star in the southern constellation of Phoenix. It is visible to the naked eye with an apparent visual magnitude of 4.95. This is a solar analogue, meaning its observed properties appear similar to the Sun, although it is somewhat more massive. At an estimated distance of around 49.5 light years, this star is located relatively near the Sun.
39 Eridani A is radiating 81.3 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,641 K. The secondary, component B, is a magnitude 8.68 G-type main-sequence star with a class of G2 V. It has 1.15 times the Sun's radius and shines with 1.37 times the luminosity of the Sun at an effective temperature of 5,816 K.
The cool component is a G2 bright giant or supergiant and is visually brighter than the hot component, so it is treated as the primary. The hot component is a late B or A type star, presumed to be a main sequence star. The observed spectrum of the primary star is G2 Ib, a yellow supergiant. It is calculated to have an absolute magnitude of −2.1.
This object is located at a distance of approximately 610 light years from the Sun based on parallax. The star is drifting further away with a radial velocity of around +27 km/s. This is a B-type main-sequence star with a stellar classification of B3V(n). It is a Be star; a rapidly-rotating star that is hosting a circumstellar disk of hot, decreted gas.
Tau7 Eridani is a solitary star in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 5.235. Using the parallax method, the distance to this star can be estimated as around 251 light years. This is an A-type main sequence star with a stellar classification of A3 Vs, where the 's' indicates it has narrow absorption lines.
The star is a B-type main sequence star with a stellar classification of B4 Vne. The 'ne' suffix indicates it is a rapidly rotating Be star that is surrounded by hot circumstellar gas. This material adds emission lines to the spectrum of the star. It has a projected rotational velocity of , with about 7.6 times the mass and 6 times the radius of the Sun.
This object is a B-type main-sequence star with a stellar classification of B6 V. It is around 22.4 million years old with 4.6 times the mass of the Sun and has a high rate of spin, showing a projected rotational velocity of 116 km/s. It is radiating 701 times the luminosity of the Sun from its photosphere at an effective temperature of 13,932 K.
With a semi-major axis of 0.055 arcseconds, this is one of the few eclipsing binaries whose components can be resolved with interferometry. The primary component of Tau Persei is a red giant with a spectral type of G8III. It has a radius 16 times that of the Sun, and is about 390 million years old. Its companion is an A-type main-sequence star.
HR 4729 is a hot class B main sequence star nearly ten times as massive as the sun. It is only about twelve million years old, but already shows signs of evolving away from the main sequence. Several studies have assigned a subgiant luminosity class to the star. The spectroscopic companion cannot be seen in the spectrum, therefore little is known about its properties.
It is drifting further away with a radial velocity of +7.5 km/s. This star has a stellar classification of G8V, indicating that it is a main-sequence star. Based upon stellar models, it has 82% of the Sun's mass and 77% of the radius. HD 14412 is spinning with a projected rotational velocity of 3.26 km/s and is about 9.61 billion years old.
Gamma Ursae Majoris is also an astrometric binary: the companion star regularly perturbs the Ae-type primary star, causing the primary to wobble around the barycenter. From this, an orbital period of 20.5 years has been calculated. The secondary star is a K-type main-sequence star that is 0.79 times as massive as the Sun, and with a surface temperature of 4,780 K.
Houk and Smith-Moore (1978) gave this object a stellar classification of A0 V, indicating it is an ordinary A-type main-sequence star. Gray and Garrison (1987) classified it as B9.5 III and noted that the spectrum is slightly variable. It is of the way through its main sequence lifetime, with 3.34 times the mass of the Sun and 2.0 times the Sun's radius.
Its distance has been estimated anywhere from one to six kpc. The General Catalogue of Variable Stars classifies it as an Orion variable, a pre-main sequence star, but other authors consider it to be a supergiant B[e] star. It has been confirmed to be a binary star system with the two stars separated by about 52 AU, but the nature of the companion is unknown.
Sigma2 Gruis is a binary star system in the southern constellation of Grus. Its apparent visual magnitude is 5.86. The pair had an angular separation of 2.7 arc seconds along a position angle of 265°, as of 1991. Located around distant, the white-hued primary component is an A-type main-sequence star of spectral type A1V, a star that is currently fusing its core hydrogen.
It is radiating 6,600 times the luminosity of the Sun. The companion star, 32 Cygni B, is smaller than the primary, with four times the Sun's mass and three times the Sun's radius. It has a much higher effective temperature of 16,200 K and is radiating over 300 times the Sun's luminosity. This star has the blue-white hue of a B7 star main sequence star.
This object is an inactive F-type main sequence star with a stellar classification of F9.5V; in between F8 and G0. This indicates it is generating energy through core hydrogen fusion. The star is similar to the Sun, but is slightly hotter and more massive. It is about 5.1 billion years old and it is spinning slowly with a projected rotational velocity of 1.3 km/s.
This is an ordinary G-type main-sequence star with a stellar classification of G0/G1V. It is a metal-rich star with an age has been calculated as being anywhere from 2.7 to 4.6 billion years. The star has 1.6 times the mass of the Sun and 1.56 times the Sun's radius. It is spinning with a projected rotational velocity of 3.5 km/s.
The primary component is a G-type main-sequence star with a stellar classification of G3V. It has a quiescent chromosphere and does not appear to be variable. The star has 18% more mass than the Sun and a 46% greater size. It is around 2.5 billion years old with a higher than solar metallicity, and is spinning with a projected rotational velocity of 3 km/s.
The stellar classification of the primary component is A0 V, matching an A-type main-sequence star. It is spinning rapidly with a projected rotational velocity of 300 km/s, giving it an oblate shape with an equatorial radius 22% larger than the polar radius. The star is radiating 156 times the Sun's luminosity from its photosphere at an effective temperature of 8,178 K.
In this case, the two stars can also be split by differential astrometry. The magnitude 4.18 primary has a mass of and the fainter secondary, . The primary is an F-type main-sequence star radiating 4.3 times the Sun's luminosity, and the magnitude 6.48 secondary is K-type with 0.6 times the luminosity of the Sun. The two orbit each other every with an eccentricity of 0.15.
At its southern end is the magnitude 0.5 star Achernar, designated Alpha Eridani. It is a blue- white hued main sequence star 144 light-years from Earth, whose traditional name means "the river's end". Achernar is a very peculiar star because it is one of the flattest stars known. Observations indicate that its radius is about 50% larger at the equator than at the poles.
32 Eridani is divisible in small amateur telescopes. 39 Eridani is a binary star also divisible in small amateur telescopes, 206 light-years from Earth. The primary is an orange-hued giant star of magnitude 4.9 and the secondary is of magnitude 8. 40 Eridani is a triple star system consisting of an orange main-sequence star, a white dwarf, and a red dwarf.
109 Piscium is a yellow hued G-type main-sequence star located about 108 light years away in the zodiac constellation of Pisces. It is near the lower limit of visibility to the naked eye with an apparent visual magnitude of 6.27. The star is moving closer to the Earth with a heliocentric radial velocity of −45.5 km/s. It has one known exoplanet.
It has 17 times the Sun's mass and is radiating as much energy as 34,000 Suns. At this rate of emission, the star has reached the end of its life as a B-type main sequence star after a relatively brief 8 million years. The outer atmosphere has an intense effective temperature of 25,000 K, which is causing it to glow with a blue- white hue.
V830 Tauri is a T Tauri star, a pre-main sequence star that has a surrounding disc producing emission lines in its spectrum. It is classified as a weak-lined T Tauri star. It is also classified as a BY Draconis variable, cool stars with starspots and chromospheric activity that vary in brightness as they rotate. The variable period of 2.74 days matches the rotation period.
WASP-45 is a K-type main-sequence star about 690 light-years away. The star age cannot be well constrained, but it is probably older than Sun. Yet, WASP-45 is enriched in heavy elements compared to Sun, having 240% of solar abundance. The star has low ultraviolet emission, therefore suspected to have a low starspot activity,, although chromospheric activity was reported elsewhere.
It is classified as B7 main sequence star with a mass of . The cluster contains another dozen or so 9th and 10th magnitude stars and many fainter stars. S Monocerotis A is a spectroscopic binary system with an orbital period of 74 years. Since 1943, the spectrum of this star has served as the MK standard for O7 by which other stars are classified.
Thuban has a spectral class of A0III, indicating its similarity to Vega in temperature and spectrum, but more luminous and more massive. It has been used as an MK spectral standard for the A0III type. Thuban is not a main sequence star; it has now ceased hydrogen fusion in its core. That makes it a white giant star, being 120 times more luminous than the Sun.
Zeta Delphini (ζ Delphini) is a star in the constellation of Delphinus. With an apparent magnitude of about 4.6, it is faintly visible to the naked eye. Parallax measurements of the system made by the Hipparcos spacecraft put it at a distance of about 220 light-years, or 67 parsecs. Zeta Delphini has a spectral type of A3V, implying it is an A-type main-sequence star.
The stellar classification of this star is A7III, matching an A-type star that is in the giant stage. However, this may be a misclassification of a main sequence star. It has also been classified as a spectroscopic binary, although no orbital elements are published. 42 Cancri is an estimated 603 million years old and is spinning rapidly with a projected rotational velocity of 195 km/s.
The astrometric companion to the primary remains unresolved. The main component is an A-type main-sequence star with a stellar classification of A1 Vb. Based upon stellar models, it has an age estimated at 212 million years. Consistency with its membership in the Columba association suggests a much younger age of 30 million years. Earlier measurements showed a high projected rotational velocity of 168 km/s.
This is a single-lined spectroscopic binary system. The ROSAT All Sky Survey discovered that Alpha Sagittarii is emitting an excess flux of X-rays, which is not expected to originate from a star of this spectral class. The most likely explanation is that the companion is an active pre-main sequence star or else a star that has just reached the main sequence.
37 Geminorum is a star located at the northwest part of the northern zodiac constellation of Gemini. Its distance from the Sun is about 56.2 light years. It is a solitary, G-type main sequence star with a stellar classification of G0 V. No extrasolar planets have yet been discovered around it. It is the target of a METI message dubbed the Teen Age Message.
Tau8 Serpentis, Latinized from τ8 Serpentis, is an A-type main sequence star in the constellation of Serpens, approximately 320 light-years from the Earth. It has an apparent visual magnitude of approximately 6.144. Although it was observed to be binary by speckle interferometry in 1985, subsequent observations show no sign of binarity, and the detection appears to have been spurious.ICCD speckle observations of binary stars.
Comparison of its properties with model evolutionary tracks suggest that it is a main sequence star about three quarters of the way through its main sequence lifetime. The apparent magnitude varies from +4.33 to +4.36 with a period of 5.03 hours. Its pulsations cause its radius to vary by 1.0% to 1.5%. At the same time its effective temperature by about above and below its mean temperature.
Measurement of the stars proper motion over time suggest changes due to an acceleration component, which may indicate it is a close binary system. The visible component has a stellar classification of G5 V, indicating it is an ordinary G-type main-sequence star that is generating energy through hydrogen fusion in its core region. Hall et al. (2007) classify it as a low-activity variable star.
Other non-pro- supernova binaries include binaries that consist out of a main sequence star (or giant) and a white dwarf. The binary Sirius AB is probably the most famous example. White dwarfs can also exist as binaries or multiple star systems that only consist out of white dwarfs. An example of a resolved triple white dwarf system is WD J1953-1019, discovered with Gaia DR2 data.
HR 2554, also known as V415 Carinae and A Carinae, is an eclipsing spectroscopic binary of the Algol type in the constellation of Carina whose apparent visual magnitude varies by 0.06 magnitudes and is approximately 4.39 at maximum brightness. Its primary is a G-type bright giant star and its secondary is an A-type main sequence star. It is approximately 553 light years from Earth.
J Centauri (J Cen) is a star in the constellation Centaurus. It is approximately 350 light years from Earth. J Centauri is a spectral class B3V main sequence star with a mean apparent magnitude of 4.5 and a luminosity 500 times that of the Sun. The temperature of the star's photosphere is nearly 24,000 K. The rotation velocity at the equator is at least 223 km/s.
Pr0201 b (also written Pr 0201 b) is an exoplanet orbiting around the F-type main sequence star Pr0201. Pr0201 b along with Pr0211 b are notable for being the first exoplanets discovered in the Beehive Cluster located in the constellation Cancer. Since Pr0201 b has a mass of about 0.5 Jupiters and an orbital period of about 4 days, it is likely a hot Jupiter.
HD 153053 is double star in the southern constellation of Ara. The brighter component is an A-type main sequence star that may be evolving into a subgiant. It has a twelfth magnitude visual companion at an angular separation of 24.7″ along a position angle of 52°. Mostly likely the two are isolated stars that happen to lie near the same line of sight.
HD 148156 is an 8th magnitude G-type main sequence star located approximately 168 light years away in the constellation Norma. This star is larger, hotter, brighter, and more massive than our Sun. Also its metal content almost twice as much as the Sun. The survey in 2015 have ruled out the existence of any additional stellar companions at projected distances from 49 to 345 astronomical units.
Alpha Caeli (α Cae, α Caeli) is a double star system in the constellation Caelum. Alpha Caeli A is an F-type main sequence star with a stellar classification of F2V and an apparent magnitude of +4.44. It has 1.48 times the mass of the Sun and 1.3 times the solar radius. The projected rotational velocity at the stellar equator is 47.8 km/s.
The name was selected in the NameExoWorlds campaign by Iraq, during the 100th anniversary of the IAU. Uruk was an ancient city of the Sumer and Babylonian civilizations in Mesopotamia. This object is an ordinary F-type main-sequence star with a stellar classification of F8 V. It is around three to 4.5 billion years old and may be evolving onto the subgiant branch.
HD 85390 b (also known as HIP 48235 b) is an extrasolar planet which orbits the G-type main sequence star HD 85390, located approximately 106 light years away The planet HD 85390 b is named Madalitso. The name was selected in the NameExoWorlds campaign by Zambia, during the 100th anniversary of the IAU. Madalitso means blessings in the native language of Nyanja in Zambia.
HD 63765 is an 8th-magnitude G-type main sequence star located approximately 106 light years away in the constellation Carina. This star is smaller, cooler, dimmer, and less massive than the Sun. It has a lower iron content than our Sun, with approximately 69% of the Sun's iron-to-hydrogen ratio. In 2009, a gas giant planet was found in orbit around the star.
The transition in primary energy production from one form to the other spans a range difference of less than a single solar mass. In the Sun, a one solar-mass star, only 1.5% of the energy is generated by the CNO cycle. By contrast, stars with 1.8 or above generate almost their entire energy output through the CNO cycle. The observed upper limit for a main-sequence star is 120–200 .
At the estimated distance of Eta Draconis, this yields a physical size of about 57 times the radius of the Sun. The companion, η Sagittarii B, was first noted by American astronomer S. W. Burnham in 1879. The two stars share a common proper motion and hence are probably gravitationally bound to each other. The secondary is likely an F-type main sequence star with an apparent magnitude of +7.77.
Gamma Serpentis is an ordinary F-type main sequence star with a stellar classification of F6 V. It is larger and more massive than the Sun, with three times the solar luminosity. Based upon its mass, it may have a convection zone in its core region. The projected rotational velocity along the equator is 10.2 km/s. It is younger than the Sun with an estimated age of 3.5 billion years.
Zeta Ursae Minoris (ζ UMi, ζ Ursae Minoris) is a star in the constellation Ursa Minor. It is a white stellar class A-type main sequence star with an apparent magnitude of +4.28. It is approximately 380 light years from Earth. Despite its classification as a main sequence dwarf star, Zeta UMi is 3.4 times the mass of the sun and its luminosity is about 200 solar luminosities.
Zeta Aurigae is moving away from Earth at a rate of per second. The second of the two Haedi or "Kids" is Eta Aurigae, a B3 class star located 243 light-years from Earth with a magnitude of 3.17. It is a B3V class star, meaning that it is a blue-white hued main-sequence star. Eta Aurigae has an absolute magnitude of −1.7 and a luminosity of .
Lambda Columbae, Latinized from λ Columbae, is a probable binary star in the southern constellation of Columba. With an apparent visual magnitude of 4.86, it is faintly visible to the naked eye. The measured annual parallax shift of 9.75 mas yields an estimated distance of roughly 335 light years. Lambda Columbae has a stellar classification of B5 V, indicating that it is a B-type main sequence star.
The star is radiating 86 times the Sun's luminosity from its photosphere at an effective temperature of 9,977 K. The fainter secondary component is an A-type main-sequence star with a class of A2 Vn. It shows a projected rotational velocity of 270 km/s and has 2.7 times the Sun's mass. The star shines with 73 times the Sun's luminosity at an effective temperature of 9,840 K.
This star is similar to the Sun, being a G-type main-sequence star with a stellar classification of G0 V. It is about 10% more massive and 17% larger than the Sun, with an estimated age of roughly four billion years and a projected rotational velocity of 3.67 km/s. The star is radiating 1.6 times the Sun's luminosity from its photosphere at an effective temperature of 6,019 K.
H Centauri (H Cen), also known as V945 Centauri, is probable triple star system located in the constellation Centaurus. From parallax measurements, it is located 113 parsecs (370 light years) from the sun. It is a member of the Lower Centaurus-Crux (LCC) subgroup of the Scorpius–Centaurus Association. This system is a double-lined spectroscopic binary formed by two B-type main- sequence star with spectral types B7V and B8.5V.
The pair show a combined stellar classification of B3 Ve, which matches a B-type main sequence star. The 'e' suffix on the class indicates this is a Be star. Alternate classifications include B4 Vnp and B4npe, with the 'n' indicating broad ("nebulous") absorption lines due to rotation and the 'p' meaning a chemically peculiar star. The two components appear to have similar visual magnitude, mass, and classification.
This visible component is an A-type main-sequence star with a stellar classification of A1V. The star is 331 million years old and is spinning with a projected rotational velocity of 107 km/s. It has 2.8 times the mass of the Sun and 3.1 times the Sun's radius. The star is radiating 110 times the luminosity of the Sun from its photosphere at an effective temperature of 9,484 K.
Ian Ridpath's Star Tales - Officina Typographica The visible member is a B-type main-sequence star with a stellar classification of B5 V, according to N. Houk and M. Smith-Moore (1978). Earlier, Hoffleit et al. (1964) had listed a class of B5 IV, suggesting a more evolved subgiant star. It is spinning rapidly, which is creating an equatorial bulge that is 6% larger than the polar radius.
Spectroscopic parallax is an astronomical method for measuring the distances to stars. Despite its name, it does not rely on the geometric parallax effect. The spectroscopic parallax technique can be applied to any main sequence star for which a spectrum can be recorded. The method depends on the star being sufficiently bright to provide a measurable spectrum, which as of 2013 limits its range to about 10,000 parsecs.
This is an ordinary K-type main-sequence star with a stellar classification of K0V. It has a modest level of chromospheric activity, and is rotating with a period of 38.6 days. The star is smaller than the Sun, with 82% of the mass of the Sun and 76% of the Sun's radius. The age of this star is 9.8 billion years, compared with 4.6 billion years for our Sun.
The planetary object orbits a (DB-type) white dwarf. It has ended its main sequence lifetime and will continue to cool for billions of years to come in the future. Based on recent studies and its mass, the star was likely an early F-type main sequence star (spectral type F0) before it became a red giant. The star has a mass of 0.6 and a radius of 0.02 (1.4 ).
The primary component of γ Equulei is a chemically peculiar star with a stellar classification of . It has a spectrum corresponding to an A9 main sequence star, but with unusual abundances of strontium, chromium, and europium. Stars with this type of spectral peculiarity are called Ap stars. The abundances of some metals are believed to be due to chemical stratification in the slowly-rotating star, unusual for hot main sequence stars.
2 Equulei is a double star system in the constellation of Equuleus. The primary component of the 2 Equ pair is an F-type main sequence star. As of 2015, the secondary had an angular separation of 2.90 arc seconds along a position angle of 213° from the primary. They form a common proper motion pair, two stars at approximately the same distance and moving in the same direction.
White dwarf mass value from Subasavage et al. 2009, in Wood model D yields MS (main sequence) mass ', and MS lifetime 0.11 Gyr, corresponding to B-type main sequence star. According to initial-final mass relation from Weidemann 2000 paper, WD 2359−434's main sequence progenitor should have mass about ' and lifespan 0.22 Gyr', and, again, should be of B spectral type. There are also other models.
This is an A-type main- sequence star with a stellar classification of A0 V. It is young with an age of around 67 million years and is spinning rapidly with a projected rotational velocity of 238 km/s. The star has 2.51 times the mass of the Sun and is radiating 42 times the Sun's luminosity from its photosphere at an effective temperature of around 11,614 K.
The brighter star has a stellar classification of B7 III-IV, with the luminosity class of III-IV suggesting that it may lie in an intermediate stage between a subgiant and a giant star. The faint companion is a K-type main sequence star with a classification of K0 V. It has a visual magnitude of 12.5 and an angular separation of 15 arcseconds from the brighter member.
It has a relatively high proper motion, traversing the celestial sphere at the rate of per year. This is an ordinary G-type main-sequence star with a stellar classification of G0 V. It has some similarities to the Sun, and thus is considered a solar analog. Brewer et al. (2016) estimate the star has 1.3 times the mass of the Sun and 1.44 times the Sun's radius.
OU Puppis (OU Pup) is a class A0 (white main-sequence) star in the constellation Puppis. Its apparent magnitude is 4.87 and it is approximately 184.4 light years away based on parallax. It is an α² CVn variable, ranging from 4.93 to 4.86 magnitude with a period of 0.92 days. Unlike the majority of star pairs, the number attached to the Bayer designation 'L' is generally a subscript: L1.
Its host star is a G-type main-sequence star that is slightly less massive than the Sun, although it is about 5% larger and has a temperature of about 6031 K. The star is a V magnitude 12.4 star in the constellation Draco. Despite the unknown age of the star, its low metallicity and fairly high space velocity suggest that KOI-4878 is older than the Sun.
U Aquilae is a binary star system in the constellation Aquila, Located approximately away from Earth. The primary star (component A) is a yellow supergiant with a radius of and a luminosity of . The secondary (component B) is a blue main-sequence star, twice the mass of the sun and around thirty times more luminous. It is hotter than the primary star at 9,300 K, but much smaller and fainter.
HD 220466 is a F-type subgiant or main sequence star in the constellation Aquarius. It has apparent magnitude 6.47 and is about 200 light-years away. In 1913, an apparent visual companion of apparent magnitude 10.3 was observed 1.9 arcseconds away from the star,CCDM 23241-2146, database entry, Catalog of Components of Double and Multiple Stars, CDS ID I/211. Accessed on line July 22, 2008.
The primary is a B-type main-sequence star with a stellar classification of B9V. It is roughly 67 million years old and is spinning with a projected rotational velocity of 149 km/s. The star has 2.7 times the mass of the Sun and 2.6 times the Sun's radius. It is radiating 66 times the luminosity of the Sun from its photosphere at an effective temperature of 10,141 K.
This is an ordinary F-type main-sequence star with a stellar classification of F0 V. The star has a high rate of spin, showing a projected rotational velocity of 123 km/s. It has 1.8 times the mass of the Sun and 2.5 times the Sun's radius. The star is radiating 16 times the luminosity of the Sun from its photosphere at an effective temperature of 7,063 K.
This yields a distance estimate of , give or take a 4 light-year margin of error. At this distance, the visual magnitude is diminished by 0.26 from extinction caused by interstellar gas and dust. The spectrum of 35 Aquilae fits a stellar classification of A0 V, indicating it is an A-type main sequence star. Compared to the Sun, it has 210% of the mass and 180% of the radius.
This object is an A-type main- sequence star with a stellar classification of A0 Vnn, where the 'n' notation indicates "nebulous" lines due to rapid rotation. It is spinning with a projected rotational velocity of 149 km/s. This star has around 2.3 times the radius of the Sun and is radiating over three times the Sun's luminosity from its photosphere at an effective temperature of 8,794 K.
This is an ordinary F-type main- sequence star with a stellar classification of F1V, which indicates it is generating energy from hydrogen fusion at its core. This energy is being radiated from its photosphere at the rate of 7.8 times the Sun's luminosity with an effective temperature of 7,380 K. 7 Andromedae is 1.1 billion years old and is spinning with a projected rotational velocity of 61 km/s.
In this case, the two stars have also been resolved using interferometry. The primary star is an F-type main-sequence star, that is 1.5 times the mass of the Sun and around twice as wide. Its companion star is 1.34 times the mass of the Sun, and 1.36 times the radius of the Sun. The two stars orbit each other every 26.3 days, and its orbital eccentricity is 0.481.
It has a combined stellar classification of F8V, matching an F-type main-sequence star, with individual massed of 1.29 and 1.05 times the mass of the Sun. Component B is of magnitude 6.72 with a class of F7V and 1.25 solar masses. The A–B pair have a separation of and a period of 1,347.653 years. This system is a source of X-ray emission with a luminosity of .
The binary pair consists of two stars separated by . The primary, component A, is an F-type main sequence star with a stellar classification of F3V. This star is about two billion years old with 52% more mass than the Sun. It forms a double star with a magnitude 8.85 companion, which is located at an angular separation of along a position angle of 331.1°, as of 2011.
Mu2 Octantis (μ2 Oct) is a binary star system of two G-type main-sequence stars. It shares the designation μ with μ1 Octantis, from which it is separated by 50 arcminutes. The primary star (A) is HD 196067, whose data is in the starbox. The secondary star (B) is HD 196068 (HIP 102128, LTT 8160), another G-type main-sequence star with an apparent magnitude of 7.18.
GJ 3379 (Giclas 99-49) is the nearest star in the Orion constellation, being around 17.5 lightyears away from the Sun. The main sequence star is a red dwarf with the spectral class M3.5V. It has an apparent magnitude of 11.33 and an absolute magnitude of 12.68, therefore, the star is not visible with the naked eye. It is located in the left upper part of the Orion constellation, below Betelgeuse.
Kepler-68 is a Sun-like main sequence star. It is known to have at least three planets orbiting around it. The outermost planet has a mass similar to Jupiter but orbits within the habitable zone. High resolution imaging observations of Kepler-68 carried out with the lucky imaging instrument AstraLux on the 2.2m telescope at Calar Alto Observatory detected a wide companion candidate approximately 11 arcseconds away.
As of 2015, the pair had an angular separation of along a position angle of 70°. The brighter primary, designated component A, has a visual magnitude of 5.27 and is an A-type main- sequence star with a stellar classification of A2V. It is 635 million years old and is spinning with a projected rotational velocity of 191 km/s. The star has 2.1 times the mass of the Sun.
Eta Antliae (η Ant, η Antliae) is the Bayer designation for a double star in the southern constellation of Antlia. The brighter component has an apparent visual magnitude of 5.222, making it visible to the naked eye. Parallax measurements of the system yield a distance estimate of from Earth. The main component has a stellar classification of F1 V, which indicates that it is an F-type main sequence star.
110 Herculis (abbreviated to 110 Her) is a star in the northern constellation of Hercules. Its apparent magnitude is 4.19, and it can be faintly seen with the naked eye, according to the Bortle scale. Based on parallax estimates made by the Hipparcos spacecraft, the star is located fairly close, about 62.7 light-years (19.21 parsecs) away. 110 Herculis has a spectrum matching that of an F-type main-sequence star.
Iota Aquarii, Latinized from ι Aquarii, is the Bayer designation for a star in the equatorial constellation of Aquarius. It is visible to the naked eye with an apparent magnitude of +4.279. Based upon parallax measurements made during the Hipparcos mission, the distance to this star is around . The spectrum of this star fits a stellar classification of B8 V, showing that this is a B-type main sequence star.
Epsilon Cassiopeiae has a stellar classification of B3 V, indicating that it is a main sequence star fusing hydrogen in its core. Cote et al. (2003) indicate that it displays the spectral properties of a Be star, even though it is not categorized as such. The presence of emission lines in the spectrum indicates the presence of a circumstellar shell of gas that has been thrown off by the star.
HD 143361 b is an extrasolar planet located approximately 194 light-years away in the constellation of Norma, orbiting the 9th magnitude G-type main sequence star HD 143361. This planet has a minimum mass of 3.0 times that of Jupiter. Because the inclination is not known, the true mass is not known. This planet orbits at a distance of 2.0 AU with an orbital eccentricity of 0.18.
Tuiren (centre) as viewed in the Sloan Digital Sky Survey. The bright star to the top-left is TYC 3020-2195-1, an A-type main-sequence star approximately 3,156 light-years away. Tuiren and its planet(s) are named after characters from The Birth of Bran, a story in the book Irish Fairy Tales by James Stephens. The book is a re-telling of various stories from Irish folklore.
Nu Phoenicis is a yellow-white main sequence star of spectral type F9V and magnitude 4.96. Lying some 49 light years distant, it is around 1.2 times as massive as our sun, and likely to be surrounded by a disk of dust. It is the closest star in the constellation that is visible with the unaided eye. Gliese 915 is a white dwarf only 26 light years away.
This is a B-type main sequence star with a stellar classification of B9 V. It has completed an estimated of its lifetime on the main sequence. With 3.56 times the mass of the Sun, it radiates 309 times the Sun's luminosity from its outer atmosphere at an effective temperature of 10,495 K. The rate of spin is relatively high, with a projected rotational velocity of 160 km/s.
The fainter magnitude 6.29 secondary, component B, is a smaller A-type main-sequence star with a class of A2 Vn. The 'n' suffix indicates wide "nebulous" lines due to rapid rotation. It is spinning with an even higher projected rotational velocity of 250 km/s. The star has about 2.59 times the Sun's radius. Asteroid 729 Watsonia occulted HIP 53417 on March 3, 2013 at 01:48.
Tau2 Serpentis, Latinized from τ2 Serpentis, is a star in the constellation of Serpens, located approximately 480 light-years from the Sun. It is a challenge to view with the naked eye, having an apparent visual magnitude of 6.22. The star is drifting closer with a radial velocity of −19 km/s. This object is a late B-type main-sequence star with a stellar classification of B9V.
The primary component is a binary system consisting of two nearly equal components with an orbital period of around and an angular separation of . It shows a combined stellar classification of B7/8V, which matches a B-type main-sequence star. The third component is a magnitude 10.0 star at a separation of with a mass similar to the Sun. It is orbiting the inner pair with a period of around .
Aries contains several stars with extrasolar planets. HIP 14810, a G5 type star, is orbited by three giant planets (those more than ten times the mass of Earth). HD 12661, like HIP 14810, is a G-type main sequence star, slightly larger than the Sun, with two orbiting planets. One planet is 2.3 times the mass of Jupiter, and the other is 1.57 times the mass of Jupiter.
This is a member of the Columba association of co-moving stars. This is a B-type main-sequence star with a stellar classification of B9V. It is around 124 million years old and is spinning rapidly with a projected rotational velocity of about 300 km/s. Mass estimates range from 2.56 to 3.24 times the mass of the Sun and it has about 3.1 times the Sun's radius.
This is a single- lined spectroscopic binary system, but the secondary has been detected using interferometry. It is a RS Canum Venaticorum variable system with eclipses. The total amplitude of variation is only about a thousandth of a magnitude. The secondary star is similar to the sun, presumably a main sequence star, while the primary is a giant star 25 times larger than the sun and two hundred times more luminous.
The secondary star, HD 109749 B, is a K-type main sequence star with an apparent magnitude of 10.3. It has a mass of about and is located at a separation of 8.4 arcseconds, which corresponds to a projected separation of 490 AU. This star has the same proper motion as the primary and seems to be at the same distance, confirming they form a physical binary system.
Sunspots are regions of lower-than- average temperatures that are associated with intense magnetic activity. The Sun has steadily increased in luminosity by 40% since it first became a main-sequence star. The Sun has also undergone periodic changes in luminosity that can have a significant impact on the Earth. The Maunder minimum, for example, is believed to have caused the Little Ice Age phenomenon during the Middle Ages.
Simplistic representation of the formation of neutron stars. Any main-sequence star with an initial mass of above 8 times the mass of the sun () has the potential to produce a neutron star. As the star evolves away from the main sequence, subsequent nuclear burning produces an iron-rich core. When all nuclear fuel in the core has been exhausted, the core must be supported by degeneracy pressure alone.
Regardless of the details, the outer surface of a protostar consists at least partially of shocked gas that has fallen from the inner edge of the disk. The surface is thus very different from the relatively quiescent photosphere of a pre-main sequence or main-sequence star. Within its deep interior, the protostar has lower temperature than an ordinary star. At its center, hydrogen-1 is not yet fusing with itself.
If the latter is the case, it is estimated to be 1.39 times as massive as the Sun. According to Bayer's atlas, it lies above the bird's beak. Marking the raven's right wing is Eta Corvi, a yellow-white main-sequence star of type F2V that is 1.52 times as massive and 4.87 times as luminous as the Sun. It is 59 light-years distant from our Solar System.
The star is drifting closer with a radial velocity of −8.9 km/s. It is a member of the Eta Chamaeleontis stellar kinematic group. This object is a G-type main-sequence star with a stellar classification of G7V. It is a BY Draconis variable that varies in brightness by about 0.10 magnitude over a period of 15.8 days, which is interpreted as the rotation period of the star.
This object is an F-type main-sequence star with a stellar classification of F7V. It is relatively young with age estimates of 763 million and 1.3 billion years, and possesses an active chromosphere. Cool spots on the surface are generating a radial-velocity signal that is modulated by the rotation period of around five days. The star is 18% larger and 20% more massive than the Sun.
The system consists of a hot B-type giant and an A-type main-sequence star. The two stars orbit each other every 38.9 days, and have a very eccentric orbit, with an orbital eccentricity of 0.731. The primary is a slowly pulsating B-type star, which causes the system to vary by 0.03 magnitudes; for that reason it has been given the variable star designation PT Serpentis.
The two components of the binary system includes a K-type giant star and a G-type main sequence star. The primary star is estimated to be 1.8 times as massive and 13 times the diameter of the Sun. The secondary star is estimated to be similar to the Sun in size and mass. They orbit their common barycenter in a period precisely estimated to be 24.64877 days.
It is a member of the nearby Sco OB2 association. This is a B-type main sequence star with a stellar classification of B2.5 Vn, where the 'n' suffix indicates nebulous lines due to spin. It is rotating rapidly with a projected rotational velocity of 331 km/s. This is giving the star an oblate shape with an equatorial bulge that is an estimated 15% larger than the polar radius.
The system is moving further from the Earth with a heliocentric radial velocity of +6.5 km/s. It is a member of the Lower Centaurus Crux sub-group of the Scorpius–Centaurus Association. The primary, component A, is a variable Be star, with the variation being modulated by rotation. It is visual magnitude 4.66 with a stellar classification of B3 V, matching a B-type main-sequence star.
WR 148 is a spectroscopic binary in the constellation Cygnus. The primary star is a Wolf-Rayet star and one of the most luminous stars known. The secondary has been suspected of being a stellar-mass black hole but may be a class O main sequence star. WR 148 shows a classic WN8h spectrum, but with the addition of weak central absorption on some of the emission lines.
This is an Ap star with a stellar classification of A2VspSiEu, where the A2V indicates it is an A-type main- sequence star, 's' means narrow "sharp" absorption, and SiEu shows abundance anomalies of the elements silicon and europium. The star is an Alpha2 Canum Venaticorum variable, meaning that the star has a strong magnetic field chromium, silicon, and strontium spectral lines. 21 Persei's period of variability is approximately 2.88 days.
Like the primary, the secondary star Gliese 667 B (GJ 667 B) is a K-type main-sequence star, although it has a slightly later stellar classification of K5V. This star has a mass of about 69% of the Sun, or 95% of the primary's mass, and it is radiating about 5% of the Sun's visual luminosity. The secondary's apparent magnitude is 7.24, giving it an absolute magnitude of around 8.02.
HR 8799 is a roughly 30 million-year-old main-sequence star located away from Earth in the constellation of Pegasus. It has roughly 1.5 times the Sun's mass and 4.9 times its luminosity. It is part of a system that also contains a debris disk and at least four massive planets. Those planets, along with Fomalhaut b, were the first exoplanets whose orbital motion was confirmed by direct imaging.
The stellar classification of this star is A1 Vn, indicating it is an A-type main-sequence star with "nebulous" lines due to rapid rotation. It is a Lambda Boötis candidate star, being classified as chemically-peculiar by Abt & Morrell (1995). Murphy et al. (2015) list the membership likelihood as uncertain. HD 3 has 2.36 times the mass of the Sun and about 1.9 times the Sun's radius.
The second-brightest star, the yellow-white subgiant star Alpha Trianguli (3.41m) with a close dimmer companion, is also known as Caput Trianguli or Ras al Muthallath, and is at the apex of the triangle. It lies around 7 degrees north-northwest of Alpha Arietis. Making up the triangle is Gamma Trianguli, a white main sequence star of spectral type A1Vnn of apparent magnitude 4.00 about 112 light-years from Earth.
HD 69830 is a main sequence star of spectral type G8V. It has about 86% of the Sun's mass, 90% of its radius, 62% of its luminosity, and 89% of its iron abundance. The star's age has been estimated at about 10.6 ± 4 billion years. HD 69830 is located about 40.7 light-years from the Sun, lying in the northeastern part of the constellation of Puppis (the Poop Deck).
This is an ordinary B-type main-sequence star with a stellar classification of B3 V. It is just 11 million years old with a high projected rotational velocity of 115 km/s. The star has an estimated 6.1 times the mass of the Sun and around 3.9 times the Sun's radius. It is radiating 573 times the Sun's luminosity from its photosphere at an effective temperature of 15,648 K.
This is a B-type main sequence star with a stellar classification of B8/9 V. It is about 76.4% of the way through its main sequence lifespan. The star is spinning rapidly with a projected rotational velocity of 264 km/s. It has an estimated 3.4 times the mass of the Sun and is radiating 210 times the Sun's luminosity from its photosphere at an effective temperature of 11,641 K.
HD 93403 is a spectroscopic binary containing two highly luminous hot blue stars. It is 10,000 light years away in the Carina Nebula in the constellation Carina. It appears to have spectral type O5.5III, but this is composed of two spectra from a blue supergiant and blue main sequence star of spectral type O5.5I and O7V respectively. The two stars orbit every 15 days with a separation that varies from to .
This is a binary star system with an orbital period of 52.1 days and an eccentricity of 0.22. Only the primary star can be directly detected, via Doppler shifts or perturbations around the system's barycenter. Using spectroscopy and astrometry, the nature of the secondary star can be inferred. The primary star is an F-type main-sequence star with a stellar classification of F8V, 4% more massive than the Sun.
This is an ordinary A-type main-sequence star with a stellar classification of A3 V, which indicates it is generating energy through hydrogen fusion at its core. It has a projected rotational velocity of 44 km/s, with 2.66 times the mass of the Sun and double the Sun's radius. The star is radiating 93 times the Sun's luminosity from its photosphere at an effective temperature of 8,472 K.
It is one of the IAU's standard velocity stars. Gray et al. (2006) assigned this star a stellar classification of , indicating it is an F-type main-sequence star with an underabundance of iron and the CH molecule in its stellar atmosphere. It is about 4.2 billion years old with 1.12 times the mass of the Sun and is spinning with a projected rotational velocity of 4.88 km/s.
The less massive companion orbits every 3.6 years and is apparently a B9.5 main sequence star, but the dynamics of the system suggest that it may actually be a pair of stars is a close orbit. The Cepheid primary pulsates regularly with a period of 6.79671 days. It is a yellow-white supergiant or bright giant that is 5.6 times as massive as the Sun and 2,500 times as luminous.
This star has a stellar classification of A1Vnn, which indicates it is an A-type main sequence star. It has 2.7 times the mass of the Sun and nearly double the Sun's radius. Gamma Trianguli is radiating about 33 times the luminosity of the Sun from its outer envelope at an effective temperature of 9,440 K, giving the star a white hue. The star is roughly 300 million years old.
30 Arietis Bb (sometimes abbreviated 30 Ari Bb) is an extrasolar planet which orbits the F-type main sequence star 30 Arietis B, located in a quadruple star system approximately 146 light years away in the constellation Aries. The gas giant planet was discovered by on Friday, November 27, 2009 by using precise radial velocity method from echelle spectrograph installed in Alfred-Jensch telescope in Karl Schwarzschild Observatory.
Chi Tauri (χ Tauri) is a star system in the constellation of Taurus. Parallax measurements made by the Hipparcos spacecraft put it at a distance of about 291 light years (89 parsecs) from Earth. The primary component has an apparent magnitude of about 5.4, meaning it is visible with the naked eye. The main component of the system is Chi Tauri A. It is a B-type main-sequence star.
It is located 0.7 degree north of the ecliptic, and thus is subject to lunar occultations. The blue-white hued primary, component Aa, is a B-type main-sequence star with a stellar classification of B3V. It was found to be a close spectroscopic binary in 1903 by American astronomers Edwin B. Frost and Walter S. Adams. The pair have an orbital period of 2.96 days and eccentricity of 0.05.
The star is drifting further away with a heliocentric radial velocity of +15 km/s. This is a B-type main-sequence star with a stellar classification of B9 V that was suspected in 1939 by Herbert Schneller of being variable. However, this may have been based on a photographic plate that was later rejected. It is listed in the General Catalogue of Variable Stars, but marked as probably constant.
This is a late B- or early A-type main-sequence star with a stellar classification of B9.5/A0V, which indicates it is generating energy via core hydrogen fusion. It has 3.4 times the mass of the Sun and is spinning with a projected rotational velocity of 74 km/s. The star is radiating 302 times the luminosity of the Sun from its photosphere at an effective temperature of 9,886 K.
HR 8768, also known as LN Andromedae, is a formerly suspected variable star in the constellation Andromeda. Located approximately away from Earth, it shines with an apparent visual magnitude 6.41, thus it can be seen by the naked eye under very favourable conditions. Its spectral classification is B2V, meaning that it's a hot main sequence star, emitting light approximately with a blackbody spectrum at an effective temperature of 18,090 K.
HR 6902 (also designated V2291 Oph) is a binary system located 790 light years away from the Sun in the Ophiuchus constellation. The system includes an orange bright giant star and a B-type main sequence star, forming an eclipsing binary of Zeta Aurigae type. The system is also surrounded by a warm circumstellar envelope and the spectra show silicon and carbon absorption up to a distance of 3.3 giant radii.
This is an A-type main-sequence star with a stellar classification of A2 Vn, where 'n' indicates nebulous absorption lines caused by fast rotation. It is spinning rapidly with a projected rotational velocity of 275 km/s. The star has about 2.2 times the radius of the Sun and it is radiating 66 times the Sun's luminosity from its photosphere at an effective temperature of 8,586 K.
This value provides a lower bound on the true semimajor axis of their orbit. The visible component is an F-type main- sequence star with a stellar classification of F5 V. It is an estimated 1.5 billion years old with 1.3 times the mass of the Sun and 1.7 times the Sun's radius. It is radiating 5.2 times the Sun's luminosity from its photosphere at an effective temperature of 6,732 K.
HD 85390 is a main sequence star of spectral class K1 located approximately 109 light years away in the constellation Vela, appearing as 8.55 magnitude star. This star is smaller, cooler, dimmer, and less massive than our Sun. Also its metal content is seven-sixths as much as the Sun. In 2009, a planet with a minimum mass of about 1/7 of Jupiter's was found in orbit around the star.
This system was discovered to be a single-lined spectroscopic binary in 1910 by American astronomer Joseph Haines Moore. The pair, component A, orbit each other with a period of 7.6497 days and an eccentricity of 0.35. The primary is a B-type star with a stellar classification of B1.5 V or B2 IV, depending on the source. This indicates it may be a main sequence star or a more evolved subgiant star. It has about 8.1 times the mass of the Sun and radiates 1,702 times the solar luminosity from its outer atmosphere at an effective temperature of 20,790 K. A third star, component B, is a magnitude 9.38 F-type main sequence star with a classification of F7 V. It has 1.25 times the mass of the Sun and radiates 2.4 times the solar luminosity at an effective temperature of 6,194 K. It lies at an angular separation of 25.1 arc seconds from the inner pair.
The three stars lie in the same orbital plane, strongly suggesting that they were formed at the same time. The masses of the primary, pre-main-sequence star and the B companion are 14.5, 2.0 and 10.6 solar masses, respectively. The age of the system is estimated to be in the range 10–13 million years. A 15th-magnitude star has a separation of 42 arcseconds, whereas a 12th-magnitude star is 95 arcseconds away.
Theta Volantis (θ Vol, θ Volantis) is a solitary star in the southern constellation of Volans. Based upon parallax measurements, is approximately 240 light years from the Sun. It has an apparent visual magnitude of 5.19, which is bright enough to be faintly visible to the naked eye. Theta Volantis is an A-type main sequence star with a stellar classification of A0 V and a mass around 2.3 times that of the Sun.
Theta Virginis (θ Vir, θ Virginis) is a multiple star system in the zodiac constellation of Virgo. Based upon parallax measurements, it is about 320 light years from the Sun. The four stars in this system have a combined apparent visual magnitude of 4.37, bright enough to be seen with the naked eye. The primary component, Theta Virginis Aa, is a white-hued A-type main sequence star with a stellar classification of A1Vs.
This star has about 12% of the Sun's mass and 16% of the Sun's radius, but only 0.2% of the Sun's luminosity. It has a stellar classification of M6 V, which indicates it is a type of main-sequence star known as a red dwarf. This is a flare star that occasionally increases in luminosity. With high probability, there appears to be a long-term cycle of variability with a period of 4.2 years.
The spectrum of Lacaille 9352 places it at a stellar classification of M0.5V, indicating it is a type of main sequence star known as a red dwarf. This was the first red dwarf star to have its angular diameter measured, with the physical diameter being about 46% of the Sun's radius. It has around half the mass of the Sun and the outer envelope has an effective temperature of about 3,626 K.
R136a1 is currently fusing hydrogen to helium, predominantly by the CNO cycle due to the high temperatures at the core. Despite the Wolf–Rayet spectral appearance, it is a young star. The emission spectrum is created by a dense stellar wind caused by the extreme luminosity, with the enhanced levels of helium and nitrogen being mixed from the core to the surface by strong convection. It is effectively a main sequence star.
It is a double-lined spectroscopic binary with an orbital period of 21.7 days and an eccentricity of 0.12. The primary component is a B-type main- sequence star with a stellar classification of B5V, indicating it is generating energy through core hydrogen fusion. The star is spinning with a projected rotational velocity of 75 km/s. It has 4.6 times the mass of the Sun and about 3.9 times the Sun's radius.
This is an ordinary A-type main-sequence star with a stellar classification of A3V. It is around 125 million years old with a high rate of spin, showing a projected rotational velocity of 144 km/s. The star has double the mass of the Sun and 1.8 times the Sun's radius. It is radiating 21 times the luminosity of the Sun from its photosphere at an effective temperature of 8,872 K.
It has a relatively high rate of proper motion, traversing the celestial sphere at the rate of per year. The primary, designated component A, is an F-type main-sequence star with a stellar classification of F7V. It is an estimated 2.51 billion years old and is spinning with a projected rotational velocity of 9.1 km/s. The star has 1.21 times the mass of the Sun and 1.26 times the Sun's radius.
The planet orbits an (M-type) pre-main-sequence star named K2-33. The star has a mass of 0.54 and a radius of 1.05 . It has a surface temperature of 3540 K and is 9.3 million years old. In comparison, the Sun is 4.6 billion years old and has a surface temperature of 5778 K. It has about the same amount of metals as the Sun, with a metallicity ([Fe/H]) of 0.
HAT-P-23 is a G-type main-sequence star about 1280 light-years away. It has a rapid rotation (rotation period equal to 7 days) for its advanced age of 4 billion years, and exhibits a strong starspot activity. The star may be in the process of being spun up by the giant planet on close orbit.The star is enriched in heavy elements, having about 140% amount of metals compared to solar abundance.
Much smaller than the primary, the white dwarf cannot be seen as a separate object, even by the Hubble Space Telescope. Gamma Crateris is a double star, resolvable in small amateur telescopes. The primary is a white main sequence star of spectral type A7V, that is an estimated 1.81 times as massive as the Sun, while the secondary—of magnitude 9.6—has 75% the Sun's mass, and is likely an orange dwarf.
Its orbit was calculated to be highly eccentric, swinging out to 10.6 astronomical units away from its star, and hence a candidate for direct imaging. BD-10°3166 is a metallic orange main sequence star of spectral type K3.0V, 268 ± 10 light-years distant from the Sun. It was found to have a hot Jupiter-type planet that has a minimum mass of 48% of Jupiter's, and takes only 3.49 days to complete an orbit.
Pictor is a constellation in the Southern Celestial Hemisphere, located between the star Canopus and the Large Magellanic Cloud. Its name is Latin for painter, and is an abbreviation of the older name Equuleus Pictoris (the "painter's easel"). Normally represented as an easel, Pictor was named by Abbé Nicolas-Louis de Lacaille in the 18th century. The constellation's brightest star is Alpha Pictoris, a white main-sequence star around 97 light-years away from Earth.
Eta Chamaeleontis, Latinized from η Chamaeleontis, is a star in the constellation Chamaeleon. It has an apparent magnitude of about 5.5, meaning that it is just barely visible to the naked eye. Based upon parallax measurements made by the Hipparcos spacecraft, this star is located some 310 light years (95 parsecs) away from the Sun. Eta Chamaeleontis has a spectral type of B8V, meaning it is a B-type main sequence star.
HD 49674 is an 8th magnitude G-type main-sequence star (spectral type G5V) located approximately 144 light years away in the constellation of Auriga. It has a very similar mass to our Sun. It is orbited by a recently discovered planet. HD 49674, and its planetary system, was chosen as part of the 2019 NameExoWorlds campaign organised by the International Astronomical Union, which assigned each country a star and planet to be named.
This is a B-type main sequence star with a stellar classification of B9.5 Vann. The suffix notation 'nn' indicates there are broad spectrum absorption lines in the spectrum associated with its rotation period. At the estimated age of just 76 million years, it is spinning rapidly with a projected rotational velocity of 308 km/s. The star has 2.92 times the mass of the Sun and 2.11 times the Sun's radius.
HD 93205, or V560 Carinae, is a binary stellar system, in the Carina Nebula (NGC 3372) in the constellation Carina. It consists of two massive O-stars that revolve around each other in 6 days. The more massive member of the pair is an O3.5 main sequence star. The spectrum shows some ionised nitrogen and helium emission lines, indicating some mixing of fusion products to the surface and a strong stellar wind.
The mass calculated from apsidal motion of the orbits is . This is somewhat lower than expected from evolutionary modelling of a star with its observed parameters. The less massive member is an O8 main sequence star of approximately . It moves in its orbit at a speed of over 300 km/s and is considered to be a relativistic binary, which causes the apses of the orbit to change in a predictable way.
It is drifting further away with a radial velocity of 18 km/s, after having come to within an estimated some 3.7 million years ago. Cowley (1972) and later Bragança et al. (2012) found a stellar classification of B3V for this object, matching a B-type main- sequence star. Houk and Swift assigned it a class of B5 III/IV, suggesting it is a more evolved star that is entering the giant stage.
This is a single-lined spectroscopic binary star system with an orbital period of 15.8 days and an eccentricity of 0.31. The primary member, component A, is an A-type main sequence star with a stellar classification of A1VsSi:. The stellar spectrum has the appearance of a hot Am star, showing overabundances of many iron-peak and heavier elements, but an underabundance of helium. In particular, it has an abnormal abundance of silicon.
The stellar classification of the primary star is F7 V, which means it is a main sequence star like the Sun. The star has 1.24 times the mass of the Sun and 0.95–1.1 times the Sun's radius. It is some 2.8 billion years old and shines with 3.66 times the Sun's luminosity. The effective temperature of the stellar atmosphere is 6,455 K, giving it the yellow-white hued glow of an F-type star.
During the NStars project, Grey et al. (2006) found a stellar classification of for this star, matching a Sun-like G-type main-sequence star with an overabundance of iron in its outer atmosphere. However, an older classification of G3 IV is still used, which would suggest it is instead a more evolved subgiant star. HD 134060 has an estimated 1.07 times the mass of the Sun and 1.15 times the Sun's radius.
It is thought to have been ejected from the OB association Sco OB 1 approximately 14 million years ago. The primary component is a B-type main-sequence star with a stellar classification of B2V. It displays microvariability with an amplitude of 0.0086 in magnitude and a frequency of 0.11316 cycles per day. The star is an estimated 14 million years old with a high rate of spin, showing a projected rotational velocity of 122.
HD 15524 is a wide binary star in the northern zodiac constellation of Aries. Located approximately away, the primary, a yellow-white subgiant or main sequence star has an apparent magnitude of 5.97, meaning that it can be viewed with the naked eye under good conditions. The secondary, separated from the primary by 12.4 arcseconds, has an apparent magnitude of 10.4. This system is the likely source of X-ray emission coming from these coordinates.
BD−10°3166 is a K-type main sequence star approximately 268 light-years away in the constellation of Crater. It was inconspicuous enough not be included in the Draper catalog (HD). The Hipparcos satellite also did not study it, so its true distance is poorly known. The distance measured by the Gaia spacecraft of 268 light years rules out a suggested companion star, LP 731-076, being its true binary star companion.
Zeta, Xi, Rho and Sigma Pegasi mark the horse's neck. The brightest of these with a magnitude of 3.4 is Zeta, also traditionally known as Homam. Lying seven degrees southwest of Markab, it is a blue-white main sequence star of spectral type B8V located around 209 light-years distant. It is a slowly pulsating B star that varies slightly in luminosity with a period of 22.952 ± 0.804 hours, completing 1.04566 cycles per day.
Aldebaran b is a giant exoplanet with at least 5.8 times the mass of Jupiter. It orbits at a distance about 45% farther than Earth does from the Sun. The equilibrium temperature of this planet is likely to be around , as it is strongly irradiated by its giant host star. Nevertheless, when Aldebaran was a main sequence star, it is likely that the planet had an equilibrium temperature comparable to that of the Earth.
This is an ordinary G-type main-sequence star with a stellar classification of G8 V. It has 1.05 times the mass of the Sun and 1.91 times the Sun's radius. The star is older than the Sun with an estimated age of 8.9 billion years and is spinning slowly with rotation period of around 47 days. It is radiating 2.66 times the Sun's luminosity from its photosphere at an effective temperature of 5,362 K.
It is itself a spectroscopic binary, although little is known about the two components. The combined spectrum is of an F4 main sequence star. It is thought to be physically associated with the supergiant primary and a member of a loose cluster of stars around Zeta Geminorum. A combination of photometry, spectroscopy, and astrometry has identified 26 stars approximately 355 parsecs away, which are likely to be members of the birth cluster of Zeta Geminorum.
It is located near the ecliptic and hence is subject to occasional occultation by the Moon. This is an F-type main sequence star with a stellar classification of F2 Vw, where the 'w' indicates weak absorption lines in the spectrum. The star is around 582 million years old with a projected rotational velocity of 29 km/s. It has 1.5 times the mass of the Sun and 1.6 times the Sun's radius.
HR 1614 (284 G. Eridani, GJ 183) is a star in the constellation Eridanus. Based upon parallax measurements, it is about distant from the Earth. It is a main sequence star with a stellar classification of K3V. The chromosphere has an effective temperature of about 4,945 K, which gives this star the orange hue characteristic of K-type stars. It has about 84% of the Sun's mass and 78% of the Sun's radius.
Rho Coronae Borealis is a yellow main sequence star of the spectral type G0V. The star is thought to have only 91 percent of the Sun's mass, along with 1.4 times its radius and 1.7 times its luminosity. It may only be 51 to 65 percent as enriched with elements heavier than hydrogen (based on its abundance of iron) and may be somewhat older than the Sun at around ten billion years old.
This is a Sun-like main sequence star with a stellar classification of G1VH-04. It has about 11% greater mass than the Sun, and is considered young with an estimated age of 400 million years. As such, it has a similar luminosity to the Sun despite being more massive. Although the abundance of elements is similar to the Sun, it is a Barium star that is overabundant in elements produced through the s-process.
Pi Piscis Austrini is moving through the galaxy at a velocity of 16.3 km/s relative to the Sun. Its projected galactic orbit carries it between 24,000 and 37,500 light-years from the center of the galaxy. This is a single-lined spectroscopic binary system with an orbital period of 178.3 days and an eccentricity of 0.53. The primary component is an F-type main-sequence star with a stellar classification of .
It is an estimated 214 million years old with 2.63 times the mass of the Sun. The fainter magnitude 8.20 companion, component B, is an F-type main sequence star with a class of F5 V. Gamma Piscis Austrini is moving through the Galaxy at a speed of 24.1 km/s relative to the Sun. Its projected Galactic orbit carries it between 21,600 and 30,800 light years from the center of the Galaxy.
HD 166066 is a star in the constellation Telescopium, located about from Earth. It has an apparent magnitude of +8.11, allowing it to be viewed with binoculars under suitable viewing conditions. The stellar classification is G0V, which indicates that it is a main sequence star. The effective temperature of its chromosphere is 5,900 K,. It has an estimated lifespan of 8.9 billion years and has about the same mass as the Sun.
Based upon its movement through space, it is a candidate member of the Ursa Major Moving Group of co-moving stars that probably share a common origin. This object is a late F-type main-sequence star with a stellar classification of F8V. It is about three billion years old and is spinning with a projected rotational velocity of 5.5 km/s. The star is 12% larger and 13% more massive than the Sun.
58 Ophiuchi is a single star in the equatorial constellation of Ophiuchus. It is visible to the naked eye as a faint, yellow-white hued star with an apparent visual magnitude of 4.86. This object is approximately 57.6 light years away based on parallax, and is drifting further from the Earth with a heliocentric radial velocity of +10 km/s. This is an ordinary F-type main- sequence star with a stellar classification of F5V.
The star is moving further from the Sun with a radial velocity of +26.6 km/s. It has a relatively high proper motion, traversing the celestial sphere at the rate of 0.237 arc seconds per year. The combination of these movements indicate this star is a member of the Hyades supercluster. Li et al. (2000) categorized this as an F-type main-sequence star with a stellar classification of F5 V(e).
In contrast, Cowley et al. (1969) found a class of B8 Vs, corresponding to a B-type main-sequence star with narrow ("sharp") absorption lines due to a relatively low projected rotation. Zorec and Royer (2012) modeled it as a dwarf star that is 67% of the way through its main sequence lifespan. It is a chemically peculiar mercury-manganese star, showing abnormally strong absorption lines of mercury and magnesium with weak lines of helium.
Parallax measurements provide a distance estimate of approximately 570 light years from the Sun. Gray and associates (1989) found a stellar classification of A8 III for this object, matching an evolved A-type giant star. Abt and Morrell (1995) listed a class of F0V, suggesting it is an F-type main-sequence star. It is a Delta Scuti variable whose brightness varies between magnitudes 6.54 and 6.59 with a period of 0.219 days.
This object is a B-type main-sequence star with a stellar classification of B9 Vs. The 's' notation indicates the spectrum appears "sharp"-lined, due to its relatively moderate projected rotational velocity of 66 km/s. It has 2.9 times the mass of the Sun and about 3.1 times the Sun's radius. The star is radiating 90 times the luminosity of the Sun from its photosphere at an effective temperature of 10,764 K.
This is an F-type main sequence star with a stellar classification of ; where the 'Fe-1' and 'CH-0.7' represent abundance deficiencies of iron and the molecule CN, respectively. It is about 1.6 billion years old and is spinning relatively quickly with a projected rotational velocity of 77.5 km/s. The outer atmosphere has an effective temperature of 6,812 K, giving it the yellow-white hue characteristic of an F-type star.
It is moving closer to the Sun with a radial velocity of −14 km/s. This star has been assigned a stellar classification of F8 V, which indicates it is an ordinary F-type main- sequence star. However, Gray et al. (2001) gave it a class of F9 IV, suggesting it is instead a subgiant star that is evolving away from the main sequence as the hydrogen fuel at its core becomes exhausted.
It is a suspected member of the Ursa Major Moving Group, although King et al. (2003) list it as a probable non-member. The brighter component is a confirmed Am star with a stellar classification of kA3hA7VmA9. This notation indicates its spectrum displays the calcium K line of an A3 star, the hydrogen lines of an A7 V, or A-type main-sequence star, and the metal lines of an A9 star.
WR 104 is a triple star system located about from Earth. The primary star is a Wolf–Rayet star, abbreviated as WR, with a B0.5 main sequence star in close orbit and another more distant fainter companion. The WR star is surrounded by a distinctive spiral Wolf–Rayet nebula, often referred to as a pinwheel nebula. The rotational axis of the binary system, and likely of the two closest stars, is directed approximately towards Earth.
Epsilon Pavonis is moving closer to the Sun with a radial velocity of −6.7 km/s. With a stellar classification of A0 Va, Epsilon Pavonis is an ordinary A-type main-sequence star that is generating energy through hydrogen fusion at its core. It is just 27 million years old with a projected rotational velocity of 85 km/s. The star has 2.2 times the mass of the Sun and 1.74 the Sun's radius.
This is a massive Be star, a rapidly rotating hot blue star which has developed a gas disk around it. It is a γ Cassiopeiae variable or shell star which has occasionally brightened to magnitude 4.0. The stellar classification of B2Ve suggests it is a B-type main-sequence star that is generating energy through core hydrogen fusion. This star is spinning rapidly with a projected rotational velocity of 190 km/s.
The visible member, component A, has a stellar classification of B2 IV-V, matching a B-type star with a luminosity class that displays mixed traits of a main sequence star and a subgiant. It is a suspected Beta Cephei variable or a slowly pulsating B star. The star has nine times the mass of the Sun and is radiating 741 times the Sun's luminosity from its photosphere at an effective temperature of .
This is equivalent to a physical distance of from Earth, give or take a 2 light year margin of error. The star is drifting closer to the Sun with a radial velocity of −26 km/s. Analysis of the spectrum of this white-hued star shows it to match a stellar classification of A2 V, indicating it is an A-type main sequence star. It has about double the size and mass of the Sun.
HD 66428 is a G-type main sequence star located approximately 179 light-years away in the constellation of Monoceros. This star is similar to our Sun with an apparent magnitude of 8.25, an effective temperature of 5705 ± 27 K and a solar luminosity 1.28. Its absolute magnitude is 11.1 while its U-V color index is 0.71. It is considered an inactive star and it is metal-rich ([Fe/H] = 0.310).
HD 125612 is a yellow main sequence star located approximately 188 light years away in the constellation Virgo. It is rich in heavy elements and has three known planets in orbit around it. A red dwarf companion star was detected in 2009 at a projected separation of 4750 AU. The possibility of a much closer companion to the primary star was also suggested, though this will need more observation to better define.
Delta1 Lyrae, Latinized from δ1 Lyrae, is a binary star system in the constellation Lyra, approximately 1,100 light years away from Earth. The two stars complete an orbit around each other about once every 88 days. They are a spectroscopic binary, meaning the separation between the two is very small, and their orbital velocity is very high. The primary member, component A, is a bluish white main-sequence star of the spectral type B2.5V.
This is a normal B-type main-sequence star with a stellar classification of B5V, which means it is generating energy via core hydrogen fusion. The star is around 11 million years old with 5.4 times the mass of the Sun and is spinning rapidly with a projected rotational velocity of 268 km/s. It is radiating 233 times the luminosity of the Sun from its photosphere at an effective temperature of 10,540 K.
An ultra-short period (USP) planet is a type of exoplanet with orbital period less than one day. At this short distance, tidal interactions lead to relatively rapid orbital and spin evolution. Therefore when there is a USP planet around a mature main-sequence star it is most likely that the planet has a circular orbit and is tidally locked. There are not many USP planets with sizes exceeding 2 Earth radii.
HD 4391 is a triple star system in the constellation Phoenix that is located at a distance of 48.7 light years from the Sun. The primary has a stellar classification of G3V, which is a G-type main sequence star. The physical properties of this star are similar to the Sun, making it a solar analog. However, it is believed to have 22% greater mass than the Sun and is only 1.2 billion years old.
Hence the grains are being replenished, presumably through collisions between larger objects. Circumstellar gas is visible in ultraviolet images from the FUSE satellite, which is likely being emitted by the circumstellar matter then driven outward by the star's radiation. The secondary, component B, has a magnitude of 7.70 and is an A-type main-sequence star. It has around 1.5 times the mass of the Sun and 7.4 times the Sun's luminosity.
Kepler-452 is a G-type main-sequence star located about 1,402 light-years away from Earth in the Cygnus constellation. Although similar in temperature to the Sun, it is 20% brighter, 3.7% more massive and 11% larger. Alongside this, the star is approximately six billion years old and possesses a high metallicity. Thus, Kepler-452 can be considered a solar twin, although it could considered to be a solar analog due to its age.
Phi Fornacis is a single star in the southern constellation of Fornax. It has a white hue and is faintly visible to the naked eye with an apparent visual magnitude of 5.13. The distance to this object is approximately 154 light years based on parallax, and it is drifting further away with a radial velocity of +19 km/s. This is an A-type main-sequence star with a stellar classification of A2.5V.
BD-17°63 b is an extrasolar planet located approximately 112.5 light-years away in the constellation of Cetus, orbiting the 10th magnitude K-type main sequence star BD-17°63. This planet has a minimum mass of 5.1 MJ and orbits at a distance of 1.34 astronomical units from the star. The distance ranges from 0.62 AU to 2.06 AU, corresponding to the eccentricity of 0.54. One revolution takes about 656 days.
This was the first exoplanet to be found orbiting a main sequence star, as opposed to planets that orbited the remains of a star. Mayor's and Queloz's discovery of an exoplanet launched great interest is searching for other exoplanets since. As of 2019, there are at least 4000 confirmed exoplanet discoveries with several more potential candidates. Mayor's work focused more on improving instrumentation for radial velocity measurements to improve detecting exoplanets and measuring their properties.
HAT-P-16 is a F-type main-sequence star about 740 light-years away. The star has a concentration of heavy elements slightly higher than solar abundance, and low starspot activity. The survey in 2015 have failed to find any stellar companions to it. The spectral analysis in 2014 have discovered the HAT-P-16 has a carbon to oxygen molar ratio of 0.58, close to Sun`s value of 0.55.
Since it was first photographed during the Palomar observatory sky survey in 1953, it had moved over by 2017. The star is moving away from the Earth with an average heliocentric radial velocity of +19.5 km/s. This is an ordinary K-type main-sequence star with a stellar classification of K0 V and no significant variability. The star has 86% of the mass of the Sun and 86% of the Sun's radius.
The primary component of this system is a B-type main sequence star with a stellar classification of B9.5 V. It is a candidate Lambda Boötis star, indicating it displays an underabundance of iron peak elements. However, it is also underabundant in oxygen, a characteristic not shared by other Lambda Boötis stars. Instead, it may be a peculiar B star. An orbiting white dwarf companion was discovered in 1998 from its X-ray emission.
This is a B-type main sequence star with a stellar classification of B3V. It has been classified as a candidate Beta Cephei variable with a period of 2.2 days, although this designation was rejected by Stankov and Handler (2005). The spectrum shows a slight underabundance of carbon, compared to the Sun. The star is around 32 million years old and is spinning with a projected rotational velocity of 101 km/s.
V518 Carinae is classified as a B-type main sequence star between B3 and B5. It is also catalogued as a helium star, a chemically peculiar star with abnormally strong helium absorption lines in its spectrum and relatively weak hydrogen lines. It is possibly a blue straggler. V518 Carinae is also a Be star, a hot star with emission lines in its spectrum due to a disk of material around the star.
HIP 57274 d is an exoplanet orbiting the K-type main sequence star HIP 57274 about 84.5 light-years (26 parsecs, or nearly km) from Earth in the constellation Cetus. It orbits within the outer part of its star's habitable zone, at a distance of 1.01 AU. The exoplanet was found by using the radial velocity method, from radial-velocity measurements via observation of Doppler shifts in the spectrum of the planet's parent star.
At that distance, the current star would be of magnitude 2.24. This is an ordinary B-type main-sequence star of spectral type B5V, a star that is generating energy through hydrogen fusion at its core. It is roughly 26 million years old with 4.7 times the mass of the Sun and 4.3 times the Sun's radius. The star has a high rate of spin, having a projected rotational velocity of 145 km/s.
This is a G-type main-sequence star with a stellar classification of G1/2V. It is a BY Draconis variable that ranges in brightness from magnitude 8.66 down to 8.77 with a rotationally-modulated period of 3.296 days. This is a young star with an age of around 60 million years and a projected rotational velocity of 15 km/s. It has about the same mass, size, and luminosity as the Sun.
The primary component is an F-type main sequence star with a stellar classification of F4 V, a star that is currently fusing its core hydrogen. It is a probable delta scuti variable showing periodicities of 4.7 and 5.5 cycles per day with amplitudes of 0.014 and 0.011 magnitudes, respectively. The secondary companion is a red dwarf with a mass of about 0.3 solar, suggesting a class of M3/M4. Ehrenreich et al.
The star has a relatively high proper motion, traversing the celestial sphere at the rate of 0.204 arc seconds per annum. This object is an ordinary F-type main-sequence star with a stellar classification of F5V. It is an estimated 2.3 billion years old and is spinning with a projected rotational velocity of 18.8 km/s. The star has 1.4 times the mass of the Sun and 1.3 times the Sun's radius.
It probably occurred when a star wandered too close to the central black hole in the galaxy, and was gravitationally torn apart and swallowed by it. Timing considerations suggest that the tidally disrupted star was a white dwarf and not a regular main sequence star. Debris now encircles the black hole in an accretion disk, which launches bipolar jets at near the speed of light. Jet plasma emits the γ- and X-rays.
Of apparent magnitude 3.3, it is 1110 ± 60 light-years from Earth. It has been estimated to be between 12.5 and 25 times as massive as the Sun, and have around 120,000 times its luminosity. Alpha Arae is a blue-white main sequence star of magnitude 2.95, that is 270 ± 20 light-years from Earth. This star is around 9.6 times as massive as the Sun, and has an average of 4.5 times its radius.
The primary star of the system has a mass of 3.2 and has a spectral type A4IV-V, meaning that it has intermediate characteristics between a main sequence star and a subgiant one. The secondary is less massive (1.3 ) but larger than the primary, so it's an evolved subgiant star and its spectral type is G5IV. The secondary component will likely evolve into a white dwarf before the primary leaves the main sequence.
The rotation produces extremely strong magnetic fields which are expected to brake the star to a slower rotation rate. Analysis of variability due to star spots on the surface show that the star rotates at different speeds at different latitudes. FK Comae Berenices is listed as a companion to the slightly brighter HD 117567. The two are not thought to be physically associated, with HD 117567 being a much closer F2 main sequence star.
As the collapse continues, an increasing amount of gas impacts the disk rather than the star, a consequence of angular momentum conservation. Exactly how material in the disk spirals inward onto the protostar is not yet understood, despite a great deal of theoretical effort. This problem is illustrative of the larger issue of accretion disk theory, which plays a role in much of astrophysics. HBC 1 is a young pre-main-sequence star.
TV Gem appears to have a very close hot companion. Its existence is inferred from an ultraviolet excess in the spectral energy distribution. The spectral type determined from the ultraviolet portion of the spectrum is B4, appearing to be a giant although it is thought that this is caused by the stellar wind from an underlying main sequence star. It is estimated to have an apparent magnitude of 11.2 and an absolute magnitude of −1.4.
TU Corvi is a Delta Scuti variable—a class of short period (six hours at most) pulsating stars that have been used as standard candles and as subjects to study astroseismology. It varies by 0.025 of a magnitude around apparent magnitude 6.53 over 59 minutes. Three star systems have confirmed planets. HD 103774 is a young yellow-white main-sequence star of apparent magnitude 7.12 that is 181 ± 5 light-years distant from Earth.
HD 139139 (also known as EPIC 249706694) is likely part of a bound pair system of main sequence stars about away from Earth in the constellation Libra. HD 139139 is a G-type main-sequence star, a little larger and more luminous than the sun, and at an almost identical temperature. It has an apparent magnitude of 9.8. The companion star is thought to be a K5-7 red dwarf away from HD 139139\.
This is a large star with 2.5 times the mass of the Sun. The spectrum matches a stellar classification of A2 V, making this a seemingly typical A-type main sequence star. However, the spectrum shows enhanced absorption lines of metals, marking this as a chemically peculiar Am star. The abundance of elements other than hydrogen and helium, what astronomers term the star's metallicity, appears around 12% higher than in the Sun.
The absolute magnitude is −0.55. The primary component of this system, component A, is an aging giant star with a stellar classification of G9III and a visual magnitude of 5.09. The secondary companion, designated component B, is a magnitude 6.94 star located at an angular separation of from the primary, along a position angle of 157°, as of 2016. It is an F-type main- sequence star with a class of F5V.
These are rare objects; it is estimated that there are no more than 20,000 class O stars in the entire Milky Way, around one in 10,000,000 of all stars. Class O main sequence stars are between and have surface temperatures between 30,000 and 50,000 K. Their bolometric luminosities are between . Their radii are more modest at around . Surface gravities are around 10,000 times that of the Earth, relatively low for a main sequence star.
With a diameter 130 times that of our Sun, it would almost reach the orbit of Venus if placed at the centre of the Solar System. The proper name Atria is a contraction of its Bayer designation. Beta Trianguli Australis is a double star, the primary being a F-type main-sequence star with a stellar classification of F1V, and an apparent magnitude of 2.85. Lying only away, it has an absolute magnitude of 2.38.
This latter star is a yellow-white main sequence star of spectral type F6V of magnitude 7.0. PZ Telescopii is another young star with a debris disk and substellar brown dwarf companion, though at 24 million years of age appears too old to be part of the Beta Pictoris moving group. HD 191760 is a yellow subgiant—a star that is cooling and expanding off the main sequence—of spectral type G3IV/V.
The secondary is likely to be a main sequence star slightly cooler than the primary, possibly an A2 spectral class. The secondary star was detected in high spatial resolution observations using the Navy Precision Optical Interferometer. The secondary star is 1.8 magnitudes (at 700 nm) fainter than the primary star and was detected at separations ranging from 6.2 to 2.6 milli-arcseconds. Eclipses were detected using data obtained with the Transiting Exoplanet Survey Satellite (TESS).
V838 Monocerotis reached maximum visual magnitude of 6.75 on February 6, 2002, after which it started to dim rapidly, as expected. However, in early March the star started to brighten again, especially in infrared wavelengths. Yet another brightening in infrared occurred in early April. In 2003 the star had returned to near its original brightness before the eruption (magnitude 15.6) but now as a red supergiant rather than a blue main-sequence star.
This is an A-type main-sequence star with a stellar classification of A1 V. It is a young star with an estimated age of just 144 million years, and has a high rate of spin with a projected rotational velocity of 173 km/s. 8 Cancri has 2.37 times the mass of the Sun and is radiating 36.6 times the Sun's luminosity from its photosphere at an effective temperature of around 10,352 K.
Sigma1 Cancri, Latinized from σ1 Cancri, is a solitary, white-hued star in the zodiac constellation of Cancer. It is faintly visible to the naked eye, with an apparent visual magnitude of +5.68. Based upon an annual parallax shift of 15.51 mas as seen from Earth, this star is located around 210 light years from the Sun. This is a chemically peculiar A-type main sequence star with a stellar classification of A8 Vas.
The current orbital elements are based upon a fraction of a single orbit, as the estimated orbital period is around 1,503 years. The system has a semimajor axis of 3.2 arc seconds and an eccentricity of 0.6. The primary member, component A, is a yellow-white hued F-type main sequence star with an apparent magnitude of +6.06 and a stellar classification of F2 V. The companion, component B, is a magnitude 7.35 star.
Epsilon Sculptoris (ε Scl, ε Sculptoris) is a binary star in the constellation Sculptor. It is approximately 91.7 light years from Earth. The primary component, Epsilon Sculptoris A, is a yellow-white F-type main-sequence star with an apparent magnitude of +5.29. Orbiting it with a separation of 4.6 arcseconds, or at least 125 Astronomical Units, is Epsilon Sculptoris B, a yellow G-type main sequence dwarf with an apparent magnitude of +8.6.
Based on measured changes in the star's motion, this is most likely an astrometric binary system. The visible component is an A-type main-sequence star with a stellar classification of A3 V. It is catalogued as an Alpha2 Canum Venaticorum variable with the designation GN Com. Rensom (1990) listed it as a suspected Am star. The system is a source of X-ray emission, which may be coming from the companion.
Mu Cephei is nearing death. It has begun to fuse helium into carbon, whereas a main sequence star fuses hydrogen into helium. When a supergiant star has converted elements in its core to iron, the core collapses to produce a supernova and the star is destroyed, leaving behind a vast gaseous cloud and a small, dense remnant. For a star as massive as Mu Cephei the remnant is likely to be a black hole.
HD 21749 (HIP 16069, 2MASS J03265922-6329569) is an orange main-sequence star about 0.68 the mass of the Sun in the constellation Reticulum, located about from Earth. On 7 January 2019, it was announced that the star has two exoplanets: a possibly rocky, hot sub-Neptune-sized exoplanet, named HD 21749b; and, a sub-Earth exoplanet, tentatively named HD 21749c (aka, TOI-186.02). These exoplanets were discovered by the Transiting Exoplanet Survey Satellite (TESS).
The eclipsing component emits a comparatively insignificant amount of light, and is not visible to the naked eye. A heated region, however, has been discovered in the center of the object. It is widely thought to be a dusty disc surrounding a class B main sequence star. Modelling the spectral energy distribution for ε Aurigae as a whole produces the best fit with a B5V star at the centre of the disc.
This is a late B- or early A-type main-sequence star that is generating energy through core hydrogen fusion. The star is 268 million years old with a relatively high rate of spin, showing a projected rotational velocity of 110. It has a higher than solar metallicity – the abundance of elements more massive than Helium. The star is radiating 350 times the Sun's luminosity from its photosphere at an effective temperature of 10,139 K.
Upsilon Coronae Borealis, Latinized from υ Coronae Borealis, is a solitary star in the northern constellation of Corona Borealis. It is a white-hued star that is dimly visible to the naked eye with an apparent visual magnitude of 5.78. The distance to this object is approximately based on parallax. This is an A-type main-sequence star with a stellar classification of A3V; a star that is currently fusing its core hydrogen.
This object is an F-type main sequence star with a stellar classification of F1 V, which indicates it is undergoing core hydrogen fusion. It is about 1.4 billion years old and is spinning with a projected rotational velocity of 45 km/s. The star has 1.6 times the mass and radius of the Sun. It is radiating 4.8 times the Sun's luminosity from its photosphere at an effective temperature of 7,088 K.
The radial velocity for Eta Tucanae displays strong oscillations, suggesting this is a spectroscopic binary system. A companion was directly detected in 2014, but this result has some unexplained anomalies. The primary component is an A-type main-sequence star with a stellar classification of A1V. It is spinning rapidly with a projected rotational velocity of 190 km/s, giving it an equatorial bulge that is 15% larger than the polar radius.
The star is drifting further away with a radial velocity of +19 km/s. This is a magnetic chemically peculiar star with a stellar classification of , showing excesses in strontium and the rare earth elements in the photosphere, among others. Houk and Swift (1999) assigned it a class of B9V, matching a B-type main sequence star. It is an Alpha2 Canum Venaticorum variable; the magnetic field is complex; not corresponding to a simple dipole.
Epsilon Tucanae (ε Tuc, ε Tucanae) is a solitary star in the southern constellation of Tucana. With an apparent visual magnitude of +4.50, it is faintly visible to the naked eye. Based upon an annual parallax shift of 8.74 mas as seen from Earth, it is located around 373 light years from the Sun. Levenhagen and Leister (2008) classified this star as B8 V, indicating a blue- white hued B-type main sequence star.
The survey in 2015 have ruled out the existence of any additional stellar companions at projected distances from 6 to 145 astronomical units. This star has a stellar classification of K3 V, which indicates that it is an ordinary K-type main sequence star. Based upon observation of regular variations in chromospheric activity, it has a rotation period of days. Stellar models give an estimated mass of around 76% of the Sun.
HD 8535 is a star located 181 light years away from the Sun in the southern constellation of Phoenix. It has a yellow hue and can be viewed using binoculars or a small telescope, having a low apparent visual magnitude of 7.70. The star is drifting further away from the Sun with a radial velocity of +2.4 km/s. This is an ordinary G-type main-sequence star with a stellar classification of G0V.
HD 215497 c is an extrasolar planet which orbits the G-type main sequence star HD 215497, located approximately 142 light years away in the constellation Tucana. This planet has at least one-thirds the mass of Jupiter and takes 568 days to orbit the star at a semimajor axis of 1.282 AU. This planet was detected by HARPS on October 19, 2009, together with 29 other planets, including HD 215497 b.
The outer atmosphere has an effective temperature of 10,504 K, giving it the blue-white hue of a B-type star. There is a close orbiting stellar companion of unknown type, with a third component at an angular separation of 5.7 arcseconds. The latter is a K-type main sequence star with a visual magnitude of 9.5. This system is among the 100 strongest stellar X-ray sources within of the Sun.
The broad nebula shown is not visible unaided, with binoculars or small amateur telescopes. It becomes clear in long-exposure photographs, such as in the first illustration on this page. Orange giant phi2 Orionis at about 116 light years is currently in the line of sight between Lambda Ori and Betelgeuse is not part of this region, often appearing so due to projection effects. HD 34989 is a Blue-white main sequence star, visible magnified only, between Lambda Ori.
It is a single-lined spectroscopic binary with an orbital period of and an eccentricity of 0.11. The primary component has a stellar classification of F8 V or F9 V, indicating it is an F-type main-sequence star. It has an estimated 1.4 times the mass of the Sun, while the companion only has 0.4 solar masses. The system is a source for radio and X-ray emissions, which may be coming from the secondary companion.
HD 4628 (96 G. Piscium) is a main sequence star in the equatorial constellation of Pisces. It has a spectral classification of K2.5 V and an effective temperature of 5,829 K, giving it an orange-red hue with a slightly smaller mass and girth than our Sun. HD 4628 lies at a distance of approximately 24.3 light years from the Sun. The apparent magnitude is just sufficient for this star to be viewed with the unaided eye.
The brighter member, component A, is an A-type main- sequence star of spectral type A2Vn, a star that is currently fusing its core hydrogen. The 'n' suffix indicates "nebulous" lines due to rapid rotation. The star is suspected of varying between magnitudes 4.42 and 4.48. It displays an infrared excess that matches a circumstellar disk of dust orbiting from the star with a mean temperature of 160 K. The secondary companion, component B, is of magnitude 7.48.
The visual magnitude +3.68 primary, component A, is either an ordinary A-type main-sequence star or somewhat evolved subgiant with a stellar classification of A2 V or A2 IV, respectively. The star is about 267 million years old with nearly double the mass of the Sun. It is spinning rapidly with a projected rotational velocity of 207 km/s. The secondary component, visual magnitude 9.7 B, lies at an angular separation of 30.6 arc seconds.
HD 60532 is a white (F-type) main sequence star located approximately 84 light-years away in the constellation of Puppis, taking its primary name from its Henry Draper Catalogue designation. It is calculated to be 1.44 times more massive than the Sun. The star is only 59% as old as our Sun (2.7 Gyr) and has metallicity of only 38% that of our Sun. In 2008, two extrasolar planets were discovered in orbit around it.
The primary component Sigma2 Ursae Majoris A, is a white-colored F-type subgiant. Its radius is about 1.75 times that of the Sun, and it is 31% more massive. The companion is an orange K-type main-sequence star that is much fainter. The two stars are separated about 4 arcseconds away, and because of their slow orbital motion the orbit is poorly known: estimates of the orbital period range from 970 years to over 1,500 years.
It is 785 million years old and is spinning with a projected rotational velocity of 92 km/s. The star has 1.34 times the mass of the Sun and is radiating 5.75 times the Sun's luminosity from its photosphere at an effective temperature of 6,908 K. The secondary, designated component B, has a visual magnitude of 7.88. It is a G-type main-sequence star with a class of G6V. The star is a suspected variable.
Circinus is a faint constellation, with only one star brighter than fourth magnitude. Alpha Circini, a white main sequence star with an apparent magnitude of 3.19, is 54 light-years away and 4° south of Alpha Centauri. Not only the brightest star in the constellation, it is also the brightest example of a rapidly oscillating Ap (RoAp) star in the night sky. It has the unusual spectral type A7 Vp SrCrE, showing increased emissions of strontium, chromium and europium.
It is 161 (±1) light-years from Earth. With a magnitude of 5.24, Nu Horologii is a white main sequence star of spectral type A2V located 169 (±1) light-years from Earth that is around 1.9 times as massive as the Sun. Estimated to be around 540 million years old, it has a debris disk that appears to have two components: an inner disk is orbiting at a distance of , while an outer disk lies from the star.
K Centauri is a possible binary star in the southern constellation of Centaurus. It has a white hue and is bright enough to be visible to the naked eye, having an apparent visual magnitude of +5.04. K Centauri is located at a distance of approximately 410 light years from the Sun based on parallax, and it has an absolute magnitude of −0.91. This is an ordinary A-type main- sequence star with a stellar classification of A1V.
Alpha Fornacis has a high proper motion and the system displays an excess of infrared emission, which may indicate the presence of circumstellar material such as a debris disk. The space velocity components of this star are (U, V, W) = (−35, +20, +30) km/s. Approximately 350,000 years ago, Alpha Fornacis experienced a close encounter with the A-type main- sequence star Nu Horologii. The two came within an estimated of each other, and both stars have debris disks.
This is an ordinary A-type main sequence star with a stellar classification of A3 V. It is 461 million years old – about 98% of the way through its main sequence lifetime – and is spinning with a projected rotational velocity of 91 km/s. The star has 2.8 times the mass of the Sun, about 2.2 times the Sun's radius, and is radiating 117 times the Sun's luminosity from its photosphere at an effective temperature of 9183 K.
This is an ordinary F-type main-sequence star with a stellar classification of F0 V. At the estimated age of two billion years, it is about 55% of the way through its main sequence lifetime and still has a relatively high rate of spin with a projected rotational velocity of 105.9 km/s. The star has 1.5 times the mass of the Sun and is radiating 6.3 times the Sun's luminosity at an effective temperature of 6,850 K.
The transits have been reported to have anomalies multiple times. Originally thought to be possibly due to the presence of an Earth-like planet, it is now accepted that the irregularities are due to a large starspot. Also discovered by the transit method is WASP-3b, with 1.75 times the mass of Jupiter. At the time of its discovery, it was one of the hottest known exoplanets, in orbit around the F-type main-sequence star WASP-3.
Kepler-90, also designated 2MASS J18574403+4918185, is a G-type main sequence star located about from Earth in the constellation of Draco. It is notable for possessing a planetary system that has the same number of observed planets as the Solar System. On 14 December 2017, NASA and Google announced the discovery of an eighth planet, Kepler-90i, in the Kepler-90 system: the discovery was made using a new machine learning method developed by Google.
The star is drifting closer with a radial velocity of −77 km/s, and is predicted to come to within in 334,000 years. At that distance the star can have a relatively small perturbing effect on comets in the Oort cloud. This is an ordinary G-type main-sequence star with a stellar classification of G0V, indicating that it is generating energy through core hydrogen fusion. It is roughly 8 billion years old and appears metal- deficient.
Despite having different distances when measured by the HIPPARCOS satellite, the two stars share a common proper motion and appear to be a natural binary system. Located 181 ± 2 light-years from Earth, Alpha Cancri (Acubens) is a multiple star with a primary component an apparent white main sequence star of spectral type A5 and magnitude 4.26. The secondary is of magnitude 12.0 and is visible in small amateur telescopes. Its common name means "the claw".
Nu2 Columbae is a solitary star in the southern constellation of Columba. It can be seen with the naked eye, having an apparent visual magnitude of 5.31. With an annual parallax shift of , it is estimated to lie about from the Sun. This star has a stellar classification of F5 V, indicating that it is an F-type main sequence star that is generating energy through the thermonuclear fusion of hydrogen into helium in its core region.
39 Leonis is the Flamsteed designation for a star in the zodiac constellation of Leo. It has an apparent visual magnitude of 5.90, so, according to the Bortle scale, it is faintly visible from suburban skies at night. Measurements made with the Hipparcos spacecraft show an annual parallax shift of 0.04385″, which is equivalent to a distance of around from the Sun. The stellar classification of 39 Leonis is F6 V, indicating it is a main sequence star.
This is an A-type main sequence star with a stellar classification of A1 Vn, where the 'n' indicates broad absorption lines due to rotation. It is spinning rapidly with a projected rotational velocity of 261.4 km/s. This is giving the star an oblate shape with an equatorial bulge that is 13% larger than the polar radius. It is shining with 70 times the solar luminosity from its outer atmosphere at an effective temperature of 9,457 K.
Astrometric measurements of the star show changes in motion that may indicate it is a member of a close binary system. This is an A-type main-sequence star with a stellar classification of A3 V. It is a suspected chemically peculiar star and formerly a candidate Lambda Boötis star. The status as a Lambda Boötis star was reviewed and changed to non-member in 2015. It is spinning rapidly with a projected rotational velocity of 196 km/s.
The primary member, designated component A, is a most likely a B-type main-sequence star with a stellar classification of B6 III. It has been identified as a slowly pulsating B-type star, and has the variable star designation V377 Vulpeculae. The star has 4.16 times the mass of the Sun and is radiating 286 times the Sun's luminosity from its photosphere at an effective temperature of 14,343 K. The secondary has an estimated 0.6–1.1 solar masses.
The internal structure of a main sequence star depends upon the mass of the star. In stars with masses of 0.3–1.5 solar masses (), including the Sun, hydrogen- to-helium fusion occurs primarily via proton–proton chains, which do not establish a steep temperature gradient. Thus, radiation dominates in the inner portion of solar mass stars. The outer portion of solar mass stars is cool enough that hydrogen is neutral and thus opaque to ultraviolet photons, so convection dominates.
The period is slowly increasing. S Sagittae has been reported as a double or triple system with a hotter main sequence star companion in a 676-day orbit. The companion, and its own possible fainter companion, are only detectable from radial velocity changes in the spectral lines of the Cepheid primary and an ultraviolet excess. Analysis of the spectrum indicates a star of spectral type A7V to F0V, and 1.5 to 1.7 times as massive as the Sun.
The star is receding from the Sun with a radial velocity of +95 km/s. This is a Sun-like G-type main-sequence star with a stellar classification of G6VFe-0.9, where the suffix notation indicates an underabundance of iron in the spectrum. The age of the star is poorly constrained, with estimated ranging from 1.6 billion years up to 10 billion. It has 95% of the mass of the Sun but 104% of the Sun's radius.
As of 2012, the pair had an angular separation of along a position angle of 357.7°. The primary component is an A-type main-sequence star with a stellar classification of A2Va+ and a visual magnitude of 6.15. The magnitude 6.84 secondary companion is a possible Am star with a stellar classification of kA5hA5mF0(IV-V), showing the calcium K line and hydrogen lines of an A5 star and the metal lines of an F0 star.
This object is an ordinary A-type main-sequence star with a stellar classification of 5 Vn, where the 'n' notation is used to indicate "nebulous" lines in the spectrum caused by rapid rotation. It is 291 million years old with a projected rotational velocity of 212 km/s. The star has 1.67 times the mass of the Sun and is radiating 27 times the Sun's luminosity from its photosphere at an effective temperature of 8,014 K.
For that reason, it has been given the variable star designation OX Aurigae. The star's spectrum matches that of an F-type main-sequence star and it has a spectral type of F2V. It has 2.5 times the mass of the Sun and 5.7 times the Sun's radius. 59 Aurigae is thought to be around 700 million years old, and is radiating 64 times the Sun's luminosity from its photosphere an effective temperature of 6,808 K.
HR 8752 may have a companion. Measurements of the ultraviolet spectral distribution show an excess that corresponds to the output of a B1 main-sequence star. The absolute magnitude was estimated at -4.5, approximately 40 times fainter than the primary at visual wavelengths. Although the stars must be fairly close (< 1400AU), no radial velocity variations have been detected in the spectral lines of the primary, and no lines are observed which can be attributed directly to the secondary.
53 Arietis (abbreviated 53 Ari) is a variable star in the northern constellation of Aries. 53 Arietis is the Flamsteed designation; it also bears the variable star designation UW Arietis. It is a B-type main sequence star with a stellar classification of B1.5 V and mean apparent magnitude of 6.10, which is near the lower limit for naked eye visibility. Based upon an annual parallax shift of 3.92 mas, the estimated distance to this star is roughly .
Iota Boötis has a companion at an angular distance of 38.6 arcseconds, easily separated with binoculars. The primary component is a white A-type main sequence dwarf with a mean apparent magnitude of +4.75. It is classified as a Delta Scuti type variable star and its brightness varies from magnitude +4.73 to +4.78 with a stable period of 38 minutes. The companion, HD 234121, is a magnitude +8.27 main sequence star belonging to spectral class K0.
This stellar pair have a nearly circular orbit with a period of nine years and a semimajor axis of 0.0615 arc seconds. They are both of visual magnitude 5.80 and display a similar spectrum, with the primary, component A, being an A-type main sequence star with a stellar classification of A5 V. This has been identified as an A-type shell star, suggesting there is a circumstellar disk of gas orbiting one or both stars.
It has 1.3 times the mass of the Sun and has expanded to 22 times the Sun's radius. The star is radiating 186 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,259 K. The unseen secondary component is most probably a main sequence star with a type between F and mid-K, although it may be a white dwarf instead. Its mass is at least 0.7–1.0 times the mass of the Sun.
The faintest member of the main σ Orionis stars is component C. It is also the closest to σ Ori AB at 11", corresponding to 3,960 astronomical units. It is an A-type main sequence star. σ Ori C has a faint companion 2" away, referred to as Cb and MAD-4. Cb is five magnitudes fainter than σ Ori Ca at infrared wavelengths, K band magnitude 14.07, and is likely to be a brown dwarf.
Delta Sagittae (Delta Sge, δ Sagittae, δ Sge) is a binary star in the constellation of Sagitta, with an apparent magnitude of +3.68. The primary component is a red M-type bright giant, and the secondary is a B-type main- sequence star. It is approximately 430 light years from Earth, based on its Gaia Data Release 2 parallax. Delta Sagittae is a spectroscopic binary with a composite spectrum, meaning that light from both stars can be detected.
As of 2018, the pair had an angular separation of along a position angle of 143°. Abt and Morrell (1995) classified the primary component as an A-type main-sequence star with a stellar classification of A8V. It is a suspected chemically peculiar star of subtype CP1 (an Am star), which Slettebak (1955) classified as kA8mF0Vp. This notation indicates the star displays the calcium K line of an A8 star and the metal lines of an F0V star.
This is a single-lined spectroscopic binary system a period of in a close, circular orbit. The pair form an eclipsing binary system that decreases from magnitude 14.9 down to 20.2, once per orbit. This object, along with AM Herculis, define a class of cataclysmic variables known as polars. The pair consist of a low mass white dwarf with a strong magnetic field, interacting with a low–mass main sequence star that has filled its Roche lobe.
HD 136118 is a star in the Serpens Caput section of the Serpens Cauda constellation. The star is too dim to be readily visible to the naked eye, having an apparent visual magnitude of 6.93. It is located at a distance of 168 light years from the Sun based on parallax, and is drifting closer with a radial velocity of −3 km/s. This object is an F-type main-sequence star with a stellar classification of F7V.
There has been some uncertainty as to the classification of this stage. Houk (1979) lists a stellar class of B8 Ib/II for HD 161840, which corresponds to a B-type bright giant/lesser supergiant mix. Multiple studies still use an older classification of B8 V, suggesting instead this is a B-type main-sequence star. Garrison and Gray (1994) assigned it a class of B8 III-IV, which would put it on the subgiant/giant star track.
ELODIE was installed at the Haute-Provence Observatory by 1994, and Queloz and Mayor began surveying the candidate systems. By July 1995, the pair had discovered that a large planet orbited 51 Pegasi; the planet was identified as 51 Pegasi b and determined to be of a Hot Jupiter. This was the first exoplanet to be discovered around a main sequence star. Queloz' and Mayor's discovery launched a more intensive search for exoplanets around other stars.
Cowley et al. (1969) found a stellar classification of A7 V for the visible component, matching an A-type main- sequence star that is generating energy through hydrogen fusion at its core. Abt and Morrell (1995) instead listed a class of A6 IV, suggesting it has left the main sequence and become a subgiant star. It is 791 million years old with a high rate of spin, showing a projected rotational velocity of 124 km/s.
The IV luminosity class indicates that it is probably a subgiant star that is in the process of evolving away from the main sequence as the supply of hydrogen at its core depletes. However, Abt (1985) gives a classification of F3 V, suggesting it is an F-type main sequence star. The measured angular diameter of the primary star is . At the system's estimated distance this yields a size of about 2.2 times that of the Sun.
Eta Arietis (η Ari, η Arietis) is the Bayer designation for a star in the northern constellation of Aries. It is dimly visible to the naked eye with an apparent visual magnitude of 5.231. With an annual parallax shift of 34.64 mas, the distance to this star is approximately . This is an F-type main sequence star with a stellar classification of F5 V. It is younger than the Sun at an age of about 2.6 billion years.
The system is drifting further away with a radial velocity of +24 km/s. This is a single-lined spectroscopic binary system with an orbital period of and an eccentricity of 0.12. The visible component is an F-type main sequence star with a stellar classification of , where the suffix notation indicates mild but anomalous underabundances of iron and the cyano radical. The secondary is most likely a helium white dwarf with 0.47 times the mass of the Sun.
Theta Persei (Theta Per, θ Persei, θ Per) is a star system 37 light years away from Earth, in the constellation Perseus. It is one of the closest naked-eye stars. The primary star is a yellowish dwarf (main sequence) star of spectral type F8V, which is somewhat larger and brighter than the Sun, but still within the range considered to have the potential for Earth-like planets. There is also a red dwarf companion of spectral type M1.
Tau1 Aquarii, Latinized from τ1 Aquarii, is the Bayer designation for a star in the equatorial constellation of Aquarius. With an apparent visual magnitude of 5.66, it is a faint naked eye that requires dark suburban skies for viewing. Parallax measurements made during the Hipparcos mission yield a distance estimate of roughly from Earth. τ1 Aquarii has a stellar classification of B9 V; right along the borderline between a B- and A-type main sequence star.
HD 34790 is a double-lined spectroscopic binary star system in the northern constellation of Auriga. It has a combined apparent magnitude of 5.66, which means it is faintly visible to the naked eye. Based upon observations by the Hipparcos satellite, it is located around 289 light years away. It has a combined stellar classification of A1Vs, matching that of an A-type main sequence star, and shines with 35 times the luminosity of the Sun.
It is moving closer to the Earth with a heliocentric radial velocity of −10 km/s. The magnitude 4.66 primary, designated component A, is an A-type main-sequence star with a stellar classification of A2V. It is 155 million years old with 2.12 times the mass of the Sun. The star is spinning with a projected rotational velocity of 155 km/s, which is creating an equatorial bulge that is 5% larger than the star's polar radius.
The primary, component A, is a magnitude 5.15 A-type main sequence star with a stellar classification of A9 V. At the estimated age of 768 million years, it is spinning rapidly with a projected rotational velocity of 220 km/s, giving the star an oblate shape with an equatorial bulge that is 15% larger than the polar radius. The star has 1.4 times the mass of the Sun. The secondary has an apparent magnitude of 7.29.
It is moving closer with a heliocentric radial velocity of −11 km/s. This is a magnetic CP star with a stellar classification of , indicating this is an A-type main-sequence star. The spectrum has very weak lines of helium but displays strong overabundances of silicon and all of the heavier elements except nickel. It is classified as an Alpha² Canum Venaticorum variable with a magnitude that varies from 6.33 to 6.41 over a period of 2.88756 days.
HIP 5158 c is an extrasolar planet, orbiting the 10th magnitude K-type main sequence star HIP 5158 about 135 lightyears away from Earth, in the constellation Cetus. It orbits its primary star at an average distance (semi- major axis) of 7.7 AU. The actual orbital period is unknown, but is estimated to be somewhere in between 9,018 and 12,200 days. It travels with an eccentricity of 0.14. It also has an estimated minimal mass 15.04 .
TW Piscis Austrini can be seen close by and is possibly associated with Fomalhaut as it lies within a light-year of it. Of magnitude 6.5, it is a BY Draconis variable. The second brightest star in the constellation, Epsilon Piscis Austrini is a blue-white star of magnitude +4.17. Located 400 ± 20 light-years distant, it is a blue-white main sequence star 4.10 ± 0.19 times as massive as the Sun, and around 661 times as luminous.
HD 11506 c is an extrasolar planet located approximately 167 light years away in the constellation of Cetus, orbiting the 8th magnitude G-type main sequence star HD 11506. It is the second planet in this system and its discovery was first claimed in 2009 by using Bayesian analysis on data previously collected by the N2K Consortium. However, in 2015 additional radial velocity measurements showed that the planetary parameters were significantly different from those determined by Bayesian analysis.
HD 16417 b (also called λ2 Fornacis b) is an extrasolar planet located approximately 83 light years away in the constellation of Fornax, orbiting the 6th magnitude G-type main sequence star HD 16417. This planet has minimum mass only 7% that of Jupiter, making this a Neptune-mass planet. In addition to this, it orbits relatively close to the host star and suffers high temperature. It is the third planet discovered in Fornax constellation on February 23, 2009.
For larger nuclei, however, no energy is released, since the nuclear force is short-range and cannot continue to act across longer nuclear length scales. Thus, energy is not released with the fusion of such nuclei; instead, energy is required as input for such processes. Fusion powers stars and produces virtually all elements in a process called nucleosynthesis. The Sun is a main-sequence star, and, as such, generates its energy by nuclear fusion of hydrogen nuclei into helium.
TRAPPIST-1 compared to the size of the Sun. TRAPPIST-1 is an ultra-cool dwarf star of spectral class that is approximately 8% the mass of and 11% the radius of the Sun. Although it is slightly larger than Jupiter, it is about 84 times more massive. High-resolution optical spectroscopy failed to reveal the presence of lithium, suggesting it is a very low-mass main-sequence star, which is fusing hydrogen and has depleted its lithium, i.e.
HR 1884 is a spectroscopic binary star in the constellation Auriga. The primary is a G type supergiant star while the secondary is probably a B type main sequence star. The possible spectroscopic binary nature of the star was first noted in 1983 by Gilbert Burki and Michel Mayor in a paper on the rate of binaries among supergiant stars. In the same year, William P. Bidelman noted that the stellar spectrum was composite indicating a companion star.
HD 219134 (also known as Gliese 892 or HR 8832) is a main-sequence star in the constellation of Cassiopeia. It is smaller and less luminous than our Sun, with a spectral class of K3V, which makes it an orange-hued star. HD 219134 is relatively close to our system, with an estimated distance of 21.25 light years. This star is close to the limit of apparent magnitude that can still be seen by the unaided eye.
8 Draconis, formally named Taiyi , is a single star in the northern circumpolar constellation of Draco. Based upon an annual parallax shift of 34.14 mas as seen from the Earth, the star is located approximately 96 light- years from the Sun. It is moving further away with a heliocentric radial velocity of +9 km/s, having come within some 2.6 million years ago. This is an F-type main-sequence star with a stellar classification of F1VmA7(n).
Lesh (1968) gave a stellar classification of B7 IVnn, which would indicate this is a somewhat evolved subgiant star. The 'nn' notation indicates especially "nebulous" absorption lines caused by rapid rotation. Houk and Smith-Moore (1978) listed it as B7/8 V, suggesting this is instead a B-type main sequence star that has not yet consumed all the hydrogen at its core. Nu Leporis is spinning rapidly with a projected rotational velocity of 285 km/s.
According to recent estimations, WR 102c is as much as 500,000 times brighter than our Sun. An initial study reporting a much higher luminosity mistakenly used photometry from a nearby star. It would have formed as a O-type main-sequence star a few million years ago and has since spent a period as a red supergiant before losing its outer layers completely. It is now almost hydrogen-free and nearing the end of its life.
This object is an ordinary A-type main-sequence star with a stellar classification of A0.5Vs, where the 's' suffix indicates "sharp" lines in the spectrum, usually due to slow rotation. It is about 272 million years old with a projected rotational velocity of 18 km/s. The star has 2.22 times the mass of the Sun and is radiating 102 times the luminosity of the Sun from its photosphere at an effective temperature of 9,692 K.
The magnitude 5.8 primary and 5.9 secondary have an orbital period of 500 years. Artist's impression of a Jupiter-mass planet orbiting the nearby star Epsilon Eridani Epsilon Eridani (the proper name is Ran) is a star with one extrasolar planet similar to Jupiter. It is an orange-hued main-sequence star of magnitude 3.7, 10.5 light-years from Earth. Its one planet, with an approximate mass of one Jupiter mass, has a period of 7 years.
Short narrated video about the protostar V1647 Orionis and its X-ray emission in 2004. In stellar evolution, an FU Orionis star (also FU Orionis object, or FUor) is a pre–main-sequence star which displays an extreme change in magnitude and spectral type. One example is the star V1057 Cyg, which became 6 magnitudes brighter and went from spectral type dKe to F-type supergiant. These stars are named after their type-star, FU Orionis.
The brighter of the two, component Aa, is a blue-white B-type bright giant or main sequence star with an apparent magnitude of +5.08. It is around 43 million years old with six times the mass of the Sun. The star is radiating 238 times the Sun's luminosity from its photosphere at an effective temperature of 9,623 K. The third member, component B, is an eighth magnitude star at an angular separation of from the primary.
TW Hydrae is a pre-main- sequence star that is approximately 80% the mass of and 111% the radius of the Sun. It has a temperature of 4000 K and is about 8 million years old. In comparison, the Sun is about 4.6 billion years old and has a temperature of 5778 K. The star's luminosity is 28% that of the Sun. The star's apparent magnitude, or how bright it appears from Earth's perspective, is 11.7.
This object is an F-type main-sequence star with a stellar classification of F9V, a star that is currently fusing its core hydrogen. It is 5.3 billion years old and is spinning with a projected rotational velocity of 8 km/s. The star has 1.2 times the mass of the Sun and 1.7 times the Sun's radius. It is radiating 3.78 times the luminosity of the Sun from its photosphere at an effective temperature of 6,105 K.
51 Pegasi b (abbreviated 51 Peg b), unofficially dubbed Bellerophon , later formally named Dimidium , is an extrasolar planet approximately 50 light-years away in the constellation of Pegasus. It was the first exoplanet to be discovered orbiting a main-sequence star, the Sun-like 51 Pegasi, and marked a breakthrough in astronomical research. It is the prototype for a class of planets called hot Jupiters. In 2017, traces of water were discovered in the planet's atmosphere.
Another definition of a relativistic star is one with the equation of state of a special relativistic gas. This can happen when the core of a massive main-sequence star becomes hot enough to generate electron-positron pairs. Stability analysis shows that such a star is only marginally bound, and is unstable to either collapse or explode. This instability is believed to limit the mass of main-sequence stars to a couple of hundred solar masses or so.
The secondary component is a yellow main sequence star with an estimated stellar class of G5, 0.92 times the Sun's mass and 0.90 times the Sun's radius. The X-ray luminosity of this star is , which is 30 times greater than the peak activity level of the Sun. This higher activity level is expected for a young star of this class. The corona has a temperature of about 5 MK, which is much hotter than the Sun's corona.
Zeta2 Muscae, Latinized from ζ2 Muscae, is a star in the southern constellation of Musca. Its apparent magnitude is 5.16. This is a white main sequence star of spectral type A5V around 330 light-years distant from Earth. Like several other stars in the constellation, it is a member of the Lower Centaurus Crux subgroup of the Scorpius–Centaurus Association, a group of predominantly hot blue-white stars that share a common origin and proper motion across the galaxy.
In 2000, this distance was revised to after correcting for probable errors. The Gaia spacecraft later measured the parallax of the star leading to an accurate distance of parsecs. The nova outburst can be explained by a white dwarf that is accreting matter from a companion; most likely a low-mass main sequence star. This close binary system has an orbital period of 1.47 hours, which is one of the shortest periods of the known classical nova.
LS I +61 303 shows the spectrum of a Be star, a B0 main sequence star with disk that produces emission lines in its spectrum. Variations in its radial velocity show that it is in orbit with an unseen compact object having a mass between . The pair orbit every 26.496 days. Although the uncertain mass of the compact object would allow it to be a neutron star, it is thought likely to be a black hole.
CC Andromedae (CC And) is a variable star in the constellation Andromeda. It is a pulsating star of the Delta Scuti type, with an apparent visual magnitude that varies between 9.19 and 9.46 with a periodicity of 3 hours. The stellar classification of CC Andromedae is F3IV-V, as it shows intermediate characteristics between a subgiant and a main sequence star. The brightness variations are the result of 7 different pulsation modes, most of which are non-radial.
It is a member of the thin disk population. This is a yellow-white hued G-type main sequence star with a stellar classification of . This notation indicates the surface abundance of iron and cyanogen are below normal for this class of star. It is around 5.7 billion years old and is spinning with a period of around 28 days. It has an estimated 1.09 times the mass of the Sun and is 1.86 times the Sun's radius.
The position of this star near the ecliptic means it is subject to lunar occultations. This is an ordinary A-type main-sequence star with a stellar classification of A1 V, which indicates it is generating energy through hydrogen fusion at its core. It has 2.6 times the mass of the Sun and about 2.5 times the Sun's radius. The star is radiating 68 times the Sun's luminosity from its photosphere at an effective temperature of 9354 K.
The primary component, τ9 Eri A, is a magnetic chemically peculiar star with a stellar classification of , indicating that it is a B-type main sequence star that shows abundance anomalies in its silicon absorption lines. It is an Alpha² Canum Venaticorum variable with a rotational periodicity of 5.954 days. The averaged strength of the stellar effective magnetic field is . Tau9 Eridani A has an estimated 326% the mass of the Sun and 3.1 times the Sun's radius.
The primary component is a B-type main sequence star with a stellar classification of B6 V. It is a slowly pulsating B-type star that undergoes radial-velocity variation with a frequency of 1.1569 times per day. The star has about five times the mass of the Sun and shines with 256 times the Sun's luminosity. The outer atmosphere has an effective temperature of 11,858 K and may possess a longitudinal magnetic field with a strength of .
This is a B-type main-sequence star with a stellar classification of B9 V. It is about of the way through its main sequence lifetime and is spinning rapidly with a projected rotational velocity of 259 km/s. The star has an estimated 3.16 times the mass of the Sun and about 2.1 times the Sun's radius. It is radiating 175 times the Sun's luminosity from its photosphere at an effective temperature of 9,908 K.
Kappa Canis Majoris, Latinized from κ Canis Majoris, is a solitary, blue-white hued star in the constellation Canis Major. It is visible to the naked eye with an apparent visual magnitude of +3.87. Based upon an annual parallax shift of 7.70 mas as seen from Earth, this star is located about 660 light years from the Sun. This is a B-type main-sequence star with a stellar classification of B1.5 Ve, although Hiltner et al.
It is a Be star with a weak circumstellar disk of gas that has around three times the radius of the host star. The stellar classification of 5 Cancri is B9.5 Vn, matching a B-type main-sequence star with "nebulous" lines due to rapid rotation. It is 36 million years old with a high projected rotational velocity of 188 km/s. The star has 2.9 times the mass of the Sun and about 3.1 times the Sun's radius.
This star is considered a solar analog—meaning that it is photometrically analogous to the Sun—and it displays no significant variability. It is a G-type main sequence star with a stellar classification of G3V. Both the mass and radius of HD 193664 differ from those of the Sun by just a few percent, although it has a somewhat lower metallicity. It may be around the same age as the Sun, being an estimated 3.9 billion years old.
Alpha Chamaeleontis, Latinized from α Chamaeleontis, is a solitary star in the southern circumpolar constellation of Chamaeleon. It has an apparent visual magnitude of 4.06 and thus is bright enough to be seen with the naked eye. With an annual parallax shift of 51.12 mas, it is located 63.8 light years from the Sun. This is an F-type main sequence star with a stellar classification of , where 'Fe−0.8' indicates an anomalously low abundance of iron.
This is an A-type main-sequence star with a stellar classification of A2:V. At the age of 237 million years, it is spinning rapidly with a projected rotational velocity of 222 km/s. This is giving the star an oblate shape with a prominent equatorial bulge that is estimated to be 21% larger than the polar radius. The star has an estimated 2.91 times the mass of the Sun and 4.1 times the Sun's radius.
NGC 6729 (also known as Caldwell 68) is a reflection/emission nebula in the constellation Corona Australis. It was discovered by Johann Friedrich Julius Schmidt in 1861. This fan-shaped nebula opens from the star R Coronae Australis toward the star T CrA to the south-east. R CrA is a pre-main- sequence star in the Corona Australis molecular complex, one of the closer star-forming regions of the galaxy at a distance of 130 pc.
Based upon parallax measurements, Mu Virginis is located some 59.6 light years from the Sun. Rijl al Awwa is an F-type main sequence star with a stellar classification of F2 V, although it does show some evidence of being a more evolved star. It has an effective temperature of 6,751 K in its outer atmosphere. The estimated age of the star is 1.5 billion years, and it has a relatively high 47.0 km/s projected rotational velocity.
This relies on distance and luminosity estimates lower than most observations. The star would be an unusually large and bright giant star for the given mass, possibly as the result of very high mass loss. To match the observed eclipse and orbital data, the secondary is a fairly normal B main sequence star of about embedded in a thick disc seen nearly edge on. The orbit itself is now fairly well determined, inclined at over 87 degrees to Earth.
This is a B-type main sequence star with a stellar classification of B9.5 V; just shy of being a cooler A-type star. It is estimated to have 2.6 times the Sun's mass and 2.3 times the radius of the Sun. It is 146 million years old, with a projected rotational velocity of 152 km/s. The star radiates 82 times the solar luminosity from its outer atmosphere at an effective temperature of 10,899 K.
Gliese 758 B (often shortened to GJ 758 B) is a brown dwarf orbiting the G-type main sequence star Gliese 758, located approximately 50 light years away, in the constellation Lyra. Gliese 758 B was detected by direct imaging using the HiCIAO instrument of the Subaru Telescope. The parameters have subsequently been revised in a follow-up study which also revealed that a putative second substellar object in the system was in fact an unrelated background star.
At present it has around 47 times the girth of the Sun. The star is radiating 735 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,365 K. Multiple star catalogues list two optical companions. Two arc- minutes away, the 8th magnitude HD 200733 is a main sequence star much closer to Earth than η Microscopii. A 14th-magnitude star one arc-minute from η Microscopii is a background object.
Beta Trianguli Australis, Latinized from β Trianguli Australis, is a double star in the southern circumpolar constellation of Triangulum Australe. It is approximately from Earth and has an apparent visual magnitude of +2.85. This star has a relatively high rate of proper motion across the celestial sphere. It is a F-type main-sequence star with a stellar classification of F1 V. Beta TrA has a 14th magnitude optical companion at an angular separation of 155 arcseconds.
Kazanasmas (1973) found a stellar classification of G5IV for this object, matching a G-type star that is evolving along the subgiant branch. It was later given a class of G8V, suggesting it is instead a G-type main-sequence star. This object is nearly twelve billion years old and is spinning slowly with a projected rotational velocity of 1.4 km/s. The star has 86% of the mass of the Sun and 95% of the Sun's radius.
This is a B-type star with a stellar classification of B2 IV-V, where the luminosity class IV-V indicates the spectrum shows mixed traits of a subgiant star and a main sequence star. It has 7−8 times the mass of the Sun and about 3.9 times the Sun's radius. The star is around nine million years old and is radiating 2,578 times the Sun's luminosity from its photosphere at an effective temperature of 21,150 K.
The pair of stars orbit each other with a period of and an eccentricity of 0.417. The plane of their orbit is inclined by an angle of 73° to the line of sight from the Earth, with a semimajor axis having an angular value of 80.64 mas. The close, eccentric orbit of the pair does not permit a stable planetary orbit in the habitable zone of either component. The primary, component A, is a magnitude 6.30 G-type main-sequence star with a stellar classification of G2 V. It has 1.13 times the mass of the Sun and is radiating double the Sun's luminosity from its photosphere at an effective temperature of 5,860 K. Component B, the magnitude 7.90 secondary, is a smaller K-type main-sequence star with a class of K2 V. It has 0.74 times the Sun's mass and shines with 0.65 times the Sun's luminosity at an effective temperature of 4,780 K. The system as a whole may be around 7.4 billion years old with a slightly higher metallicity than the Sun.
This object is an ordinary G-type main-sequence star with a stellar classification of G0V, which indicates it is generating energy via hydrogen fusion at its core. It is around 1.6 billion years old and is spinning with a projected rotational velocity of 5 km/s. The star has 112% of the mass of the Sun and 106% of the Sun's radius. The spectrum shows a higher than solar abundance of elements other than hydrogen and helium – what astronomers term the metallicity.
50 Persei is a star in the constellation Perseus. Its apparent magnitude is 5.52, which is bright enough to be seen with the naked eye. Located around distant, it is a White main-sequence star of spectral type F7V, a star that is currently fusing its core hydrogen. In 1998 the star was named a candidate Gamma Doradus variable with a period of 3.05 days, which would means it displays variations in luminosity due to non-radial pulsations in the photosphere.
109 Virginis is a single, white-hued star in the zodiac constellation of Virgo, located some 134.5 light years away from the Sun. It is the seventh- brightest member of this constellation, having an apparent visual magnitude of +3.72. This is an A-type main-sequence star with a stellar classification of A0 V, and is a suspected chemically peculiar star. However, Abt and Morrell (1995) gave it a class of A0 IIInn, matching a giant star with "nebulous" lines.
The primary member of this system, component A, is a Sun-like G-type main-sequence star with a stellar classification of G5V. Estimates of its age are five to seven billion years old, and it is spinning with a leisurely projected rotational velocity of 2.3 km/s. The star is metal rich, with nearly the same mass, radius, and luminosity as the Sun. Orbiting this star is a giant planet and a brown dwarf; the latter has been directly imaged.
Regulus is a multiple star system consisting of at least four stars. Regulus A is the dominant star, with a binary companion 177" distant that is thought to be physically related. Regulus D is a 12th magnitude companion at 212", but is an unrelated background object. Regulus A is a binary star consisting of a blue-white main sequence star of spectral type B7V, which is orbited by a star of at least 0.3 solar masses, which is probably a white dwarf.
Xi Orionis (ξ Orionis) is a binary star system in the northeastern part of the constellation of Orion, well above the red giant star, Betelgeuse in the sky. It lies next to another blue main-sequence star, Nu Orionis which is somewhat closer at 520 light years. The apparent visual magnitude of Xi Orionis is 4.47, which is bright enough to be seen with the naked eye. The distance to this star, as determined using the parallax method, is roughly 610 light years.
It is suspected to be a main sequence star with its own compact accretion disc. The best images of the disc and stars, taken using the PIONIER interferometer, show the primary star to be 0.5 mas across, the secondary to be an unresolved point source 0.91 mas away, and the circumbinary disc to be 14.15 mas in diameter. The disc is oriented at 19° to the plane of the sky aligned at an angle of about 6° away from N-S.
K2-33b (also known by its EPIC designation EPIC 205117205.01) is a very young super-Neptune exoplanet, orbiting the pre-main-sequence star K2-33. It was discovered by NASA's Kepler spacecraft on its "Second Light" mission. It is located about 456 light-years (140 parsecs) away from Earth in the constellation of Scorpius. The exoplanet was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured.
This object is a K-type main-sequence star with a stellar classification of K0 V. It is an inactive, metal-rich star. Age estimates range from 1.8 up to 7 billion years old, and it is spinning with a projected rotational velocity of 4.5 km/s. The star has 98% of the mass of the Sun and 89% of the Sun's radius. It is radiating 60% of the luminosity of the Sun from its photosphere at an effective temperature of 5,380 K.
Lacaille mistakenly named this star Mu Doradus, but had recorded its Right Ascension one hour too low. Lacaille named two neighbouring stars Eta Pictoris. Eta2 Pictoris, also known as HR 1663, is an orange giant of spectral type K5III and apparent magnitude 5.05. 474 light-years distant, it has a diameter 5.6 times that of the Sun. Eta1 Pictoris, also known as HR 1649, is 85 light-years distant and is a main sequence star of spectral type F5V and visual magnitude 5.38.
It is around five times as massive as our Sun. Beta Muscae is a binary star system around 341 light-years distant that is composed of two blue-white main-sequence stars of spectral types B2V and B3V that orbit each other every 194 years. They are eight and six times as massive as the Sun, respectively, and have about 3.5 times its diameter. Zeta2 Muscae is a white main sequence star of spectral type A5V around 330 light- years distant from Earth.
There are 37 stars brighter than apparent magnitude 6.5 in the constellation; three are brighter than magnitude 4.5. 46 Leonis Minoris, an orange giant of magnitude 3.8, is located some 95 light-years from Earth. At magnitude 4.4, Beta Leonis Minoris is the second-brightest star and the only one in the constellation with a Bayer designation. It is a binary star, the brighter component of which is an orange giant and the fainter a yellow-white main sequence star.
The spectrum of this star matches a stellar classification of F8 V, indicating this is an ordinary F-type main-sequence star. It is around 5.3 billion years old and is spinning with a projected rotational velocity of 5 km/s. The star has 1.2 times the mass of the Sun, 1.93 times the Sun's radius, and has near solar abundances of elements. The star is radiating 4.24 times the Sun's luminosity from its photosphere at an effective temperature of 5,908 K.
It has an absolute magnitude of −0.5. This is a B-type main- sequence star with a stellar classification of B7V, which means it is currently generating energy through hydrogen fusion at its core. It has 3.75 times the mass of the Sun and a fairly high rate of spin, showing a projected rotational velocity of 113 km/s. The star is radiating 245 times the luminosity of the Sun from its photosphere at an effective temperature of 13,186 K.
Eta1 Coronae Australis, Latinized from η1 CrA, is a suspected astrometric binary star system in the constellation of Corona Australis. It is visible to the naked eye as a dim, white-hued point of light with an apparent visual magnitude of 5.456. Parallax measurements put it at a distance of 317 light- years away from the Sun. The visible component is an A-type main-sequence star with a stellar classification of A3V, which indicates it is generating energy through core hydrogen fusion.
This well-studied star has a stellar classification A7 V, indicating it is an A-type main-sequence star that is generating energy through hydrogen fusion at its core. It has 1.8 times the mass of the Sun and double the Sun's radius. The star is radiating 13.3 times the Sun's luminosity from its photosphere at an effective temperature of 7,734 K. Lambda Piscium is around 583 million years old and is spinning with a projected rotational velocity of 70 km/s.
The star is also undergoing intense mass-loss HR 4049 has an unseen companion, detected from variations in the doppler shift of its spectral lines. The properties of the companion can only be estimated by making certain assumptions about the inclination of the orbit and the mass function. Given those assumptions, it is thought to be a low luminosity main sequence star. HR 4049 is an unusual variable star, ranging between magnitudes 5.29 and 5.83 with a period of 429 days.
This is a single-lined spectroscopic binary star system with an orbital period of 36.5 days and an eccentricity of roughly 0.3. The visible component is a B-type main-sequence star with a stellar classification of B7 V. It is spinning rapidly with a projected rotational velocity of 212 km/s. The star has 4.2 times the mass of the Sun and is radiating around 611 times the Sun's luminosity from its photosphere at an effective temperature of 9,908 K.
This object is a member of the Alpha Persei Cluster. This is a B-type main-sequence star with a stellar classification of B3 V. During the 1930s it was reported to have a variable radial velocity, but that may instead have been due to instrument error. The star has a high rate of spin, showing a projected rotational velocity of 120 km/s. It has 6.8 times the mass of the Sun and about 3.9 times the Sun's radius.
This allows the orbital elements to be computed, as well as the individual masses of the two stars. The stars complete their highly elliptical orbit every 107 days. The primary star has a stellar classification of A5 V, which means it is an A-type main-sequence star that is generating energy through the thermonuclear fusion of hydrogen in its core region. The NStars project gives the star a spectral type of kA4 hA5 mA5 Va under the revised MK spectral classification system.
This is a single-lined spectroscopic binary with an orbital period of and an eccentricity of 0.39. The value of Where a is the actual semimajor axis and i is the orbital inclination. for the primary is , providing a lower bound for the semimajor axis. Griffin (2011) noted that the mass of the secondary component is likely to be at least equal to that of the Sun, which, for an ordinary main sequence star, should make it visible in the spectrum.
Pi1 Orionis (π1 Ori, π1 Orionis) is a star in the equatorial constellation of Orion. It is faintly visible to the naked eye with an apparent visual magnitude of 4.74. Based upon an annual parallax shift of 28.04 mas, it is located about 116 light years from the Sun. This is an A-type main sequence star with a stellar classification of A3 Va. It is a Lambda Boötis star, which means the spectrum shows lower than expected abundances for heavier elements.
This star has a stellar classification of A3 IV–Vn, showing a spectrum with traits intermediate between an A-type main-sequence star and an evolving subgiant star. The 'n' suffix indicates "nebulous" absorption lines due to rapid rotation. It is about 400 million years old with a high projected rotational velocity of 243 km/s. This rate of spin is giving the star an oblate shape with a pronounced equatorial bulge that is an estimated 28% wider than the polar radius.
This is an ordinary G-type main-sequence star with a stellar classification of G0V. The Sun somewhat dwarfs HD 81040 in terms of physical characteristics: it has 87% of the Sun's mass and 91% of the radius of the Sun. It is spinning with a projected rotational velocity of 5.3 km/s, and has near solar metallicity. The age of the star is not precisely known; the ELODIE spectrograph suggested 0.8 Gyr and found it to have a young dust disk.
KOI-4878 star KOI-4878.01 is an exoplanet candidate that orbits the F-type main-sequence star KOI-4878. It is located about 1075 light years (329 parsecs) from Earth. The features of the planet are very similar to that of Earth, and if it is confirmed, it would have an Earth Similarity Index (ESI) rating of 0.98 or 98%, which would make it one of the most Earth-like planets found. The orbital period of the exoplanet is around 449 Earth days.
OGLE-2005-BLG-390Lb was once considered one of the smallest known extrasolar planets around a main sequence star, possibly rocky, with a mass around 5.5 times that of the Earth. The orbital radius (assuming a circular orbit) of the planet is 2.6 AU, however the orbital elements are unknown. Based on its low mass and estimated temperature of around 50 K, the planet is thought to consist mainly of ices, like Pluto or Uranus, rather than being a Jupiter-like gas giant.
Epsilon Apodis, Latinized from ε Apodis, is the Bayer designation for a star in the southern circumpolar constellation of Apus. It has an apparent visual magnitude of 5.06, which is bright enough to be viewed from dark suburban skies. Based upon parallax measurements, it is at a distance of roughly from Earth. Based upon a stellar classification of B3 V, this is a massive, B-type main sequence star that is generating energy through the fusion of hydrogen at its core.
N76A is the small dense HII region SE of AB7, part of the "ring", while AB7 lies at the centre of the less dense nebulosity within the ring. It may already be the home of a new generation of stars; N76A hosts at least five hot young stars, including a probable O9 main sequence star at its centre. A nearby unusual oxygen-rich supernova remnant has been intensively studied. It is visible as the knot of filaments growing green from ionised oxygen emission.
It is a G-type main-sequence star with a stellar classification of G1 V. Compared to the Sun, this star has a higher abundance of elements more massive than helium. This indicates it belongs to a class of stars called metal-rich. The star is slightly older than the Sun, but it has slightly more mass and has a larger radius. It is radiating 2.24 times the luminosity of the Sun from its photosphere at an effective temperature of 5,973 K.
This is a spectroscopic binary system with a close circular orbit taking just 0.945 days to complete. Despite their proximity, this does not appear to be a contact binary system. The orbital plane of the two stars lies near the line of sight, so they form an Algol-type eclipsing binary. The first component of the system is an A-type main sequence star with a stellar classification of A2 V. Its companion is giant star with a classification of K0 III.
It is moving closer to the Earth with a heliocentric radial velocity of −23 km/s. Cowley et al. (1969) assigned this star a stellar classification of A3 IV, matching an evolving subgiant star that has exhausted the hydrogen at its core. Houk and Swift (1999) reassigned it as an A-type main-sequence star with a class of A1 V. It has nearly three times the mass of the Sun and is spinning with a projected rotational velocity of 70 km/s.
At that distance, the visual magnitude of the star is diminished by an extinction of 0.108 due to interstellar dust. This is an A-type main sequence star with a stellar classification of A2 Va. Although it was one of the first stars to be cataloged as a Lambda Boötis star, Murphy et al. (2015) don't consider it to be a member of this population. The star has nearly twice the mass of the Sun and about 1.1 times the Sun's radius.
However, component C, an F-type main sequence star of magnitude 7.86, shares a common proper motion with component A and thus they form a system. This member is also a single-lined spectroscopic binary, having a period of 2.9934 days. The final member of the system, now designated component Cb, is a white dwarf star that is separated from the C, or rather Ca pair by . If it is indeed bound to Ca, its orbital period is around 1,300 years.
However, the Bright Star Catalogue (1964) listed it as a B-type main-sequence star with a class of B5 V, and multiple sources use this instead. The star is roughly 65 million years old with a projected rotational velocity of 20 km/s. It has an estimated 5.7 times the mass of the Sun and about 3.4 times the Sun's radius. 15 Aquarii is radiating 822 times the Sun's luminosity from its photosphere at an effective temperature of 14,318 K.
The inner pair of this triple star system form a spectroscopic binary with an orbital period of 6.321 years, a moderate orbital eccentricity of 0.173, and a combined visual magnitude of 5.19. The primary component of this pair has a stellar classification of G8.5 IV, with the luminosity class of IV indicating this is a subgiant star. At an angular separation of 13.0 arcseconds from this pair is a magnitude 7.52 K-type main sequence star with a classification of K2 V.
This is an F-type main-sequence star with a stellar classification of F3 V. Older surveys gave a class of F5 IV, showing the luminosity class of a subgiant star. It shows strong evidence for short-term chromospheric variability, although it is not optically variable. 18 Boötis is an estimated 1.15 billion years old and is spinning with a projected rotational velocity of 40.5 km/s. It has 1.3 times the mass of the Sun and 1.4 times the Sun's radius.
It is a chemically peculiar star of the HgMn type, with a spectrum that displays anomalous overabundances of mercury, manganese, and silicon. This component is most likely a single-lined spectroscopic binary with an unknown companion. Its magnitude 5.76 visible companion, π2 Boötis, is a white-hued A-type main-sequence star with a class of A6 V. As of 2010, the pair were separated by arcseconds on the sky along a position angle of . This corresponds to a projected separation of .
The visible component is an ordinary A-type main-sequence star with a stellar classification of A0 Vs, where the 's' notation indicates "sharp" absorption lines. It is 337 million years old with a moderate rotation rate, showing a projected rotational velocity of 75 km/s. The star has 2.87 times the mass of the Sun and about 2.7 times the Sun's radius. It is radiating 113 times the Sun's luminosity from its photosphere at an effective temperature of 9,441 K.
The mass of the black hole in GRO J0422+32 falls in the range 3.66 to 4.97 solar masses. This is the smallest yet found for any stellar black hole, and near the theoretical upper mass limit (~2.7 ) for a neutron star. Further analysis in 2012 calculated a mass of , which raises questions as to what the object actually is. It is also known to have a companion M-type main-sequence star, V518 Per,General Catalogue of Variable Stars, 3rd ed.
The main ionizing star in this nebula is HD 37061 (variable star designation NU Ori), which is positioned near the center of the H II region and located from the Sun. This is a triple star system with the brighter component being a single-lined spectroscopic binary. The main component is a blue-white hued B-type main-sequence star with a stellar classification of B0.5V or B1V. It has times the mass of the Sun and times the Sun's radius.
IK Pegasi (or HR 8210) is a binary star system in the constellation Pegasus. It is just luminous enough to be seen with the unaided eye, at a distance of about 154 light years from the Solar System. The primary (IK Pegasi A) is an A-type main-sequence star that displays minor pulsations in luminosity. It is categorized as a Delta Scuti variable star and it has a periodic cycle of luminosity variation that repeats itself about 22.9 times per day.
49 Orionis (center) In the past 49 Orionis was reported as a spectroscopic binary and an orbit was computed with a period of 445.74 days and an eccentricity of 0.549. But it was later determined to be single. This object is an A-type main-sequence star with a stellar classification of A4Vn, where the 'n' suffix indicates broadened "nebulous" lines caused by rapid rotation. It is around 284 million years old with a projected rotational velocity of 186 km/s.
The brighter member, designated component A, is an aging giant star with a stellar classification of K5III. It is reported as a semi-regular variable with magnitude ranging from 4.68 to 4.72 over 141 days, although the General Catalogue of Variable Stars describes this as unconfirmed by subsequent observations. It has the variable star designation CI Orionis, while 31 Orionis is the Flamsteed designation. The magnitude 10.2 companion star, component B, is an F-type main-sequence star with a class of F7V.
This ordinary G-type main-sequence star is considered a solar analog, having physical properties sufficiently similar to the Sun. It has a stellar classification of G5 V and is around 4.5 billion years old. The mass is similar to the Sun, although it is cooler and has a lower luminosity. Due to this similarity, HD 172051 has been selected as an early target star for both the Terrestrial Planet Finder and Darwin missions, which seek to find an Earth-like extrasolar planet.
Zeta Eridani is a single-lined spectroscopic binary system with an orbital period of 17.9 days and an eccentricity of 0.14. The primary is a mild Am star with a stellar classification of kA4hA9mA9V. This notation indicates this is a main-sequence star with the Ca-II K absorption line strength (k) of an A4 star, and the hydrogen lines (h) and metallic lines (m) of an A9 star. It has about 185% of the Sun's mass and 10.3 times the Sun's radius.
Psi Eridani, Latinized from ψ Eridani, is a star in the constellation Eridanus. With an apparent visual magnitude is 4.81, it can be seen with the naked eye on a clear, dark night. Based upon an annual parallax shift of 4.41 milliarcseconds, it is located roughly 740 light years away from the Sun. This is a B-type main sequence star with a stellar classification of B3 V. However, Houk and Swift (1999) classed it as a more evolved subgiant star.
Aquila X-1 (frequently abbreviated to Aql X-1) is a low-mass x-ray binary (LMXB) and the most luminous X-Ray source in the constellation Aquila. It was first observed by the satellite Vela 5B which detected several outbursts from this source between 1969 and 1976. Its optical counterpart is variable, so it was named V1333 Aql according to the IAU standards. The system hosts a neutron star that accretes matter from a main sequence star of spectral type K4.
It is a type III planet, making it cloudless and blue, making it look like a larger version of Uranus and Neptune. It has a mass around 35 times that of Earth. It has a similar density to Saturn, 0.60 g/cm3, giving it a radius 6.56 times that of the Earth. It orbits an F-type main-sequence star at a distance of 0.305 astronomical units (au), with a period of 54.32031 days, making its orbit smaller than that of Mercury's.
Based upon an annual parallax shift of , it is located at a distance of around from Earth. At that distance, the visual magnitude of the star is diminished by 0.15 from extinction caused by intervening gas and dust. Although Iota Aquilae is listed in star catalogues as a giant star, calculations of its dimension show that in reality it is a main-sequence star. It has nearly five times the mass of the Sun and five to six times the Sun's radius.
This massive, B-type main-sequence star has a stellar classification of B1 V. It is a Beta Cephei variable, ranging from 5.01 to 4.96 magnitude with a period of 0.19 days. Closer examination shows there are three frequencies present, consisting of 5.22994, 0.17017, and 4.88956 cycles per day. At one point it was thought to be a marginal Be star, but this was not confirmed. The star is spinning rapidly with a projected rotational velocity of 274 km/s.
It is a member of the Beta Pictoris moving group, a set of ~12 million year old stars that share a common motion through space. This is an A-type main-sequence star with a stellar classification of A0 V, and is suspected to be chemically peculiar. It is a young star, just 10 million years old, with a projected rotational velocity of 39 km/s. The mass of the star is greater than the Sun's, with De Rosa et al.
This is a long-period spectroscopic binary with an orbital period of approximately 15,000 days (41 years) and an overall apparent visual magnitude of approximately 3.28. The primary of the spectroscopic binary has a stellar classification of K3 III, indicating that it is a giant star. It most likely evolved from a F-type main sequence star after consuming the hydrogen at its core. The secondary is a relatively faint K-type dwarf, which has been imaged using a stellar coronagraph.
Delta Arae, Latinized from δ Arae, is the Bayer designation for a double star in the southern constellation Ara. It has an apparent visual magnitude of 3.62 and is visible to the naked eye. Based upon an annual parallax of 16.48 mas, it is about distant from the Earth. Delta Arae is massive B-type main sequence star with a stellar classification of B8 Vn. The 'n' suffix indicates the absorption lines are spread out broadly because the star is spinning rapidly.
Sigma Arae (σ Ara, σ Arae) is the Bayer designation for a star in the southern constellation of Ara. It is visible to the naked eye with an apparent visual magnitude of +4.575. The distance to this star, based upon an annual parallax shift of 8.62 mas, is around . This is an A-type main sequence star with a stellar classification of A0 V. Unusually for an A-type star, X-ray emissions with a luminosity of have been detected from Sigma Arae.
Zeta Arietis, Latinized from ζ Arietis, is the Bayer designation for a star in the northern constellation of Aries. It is dimly visible to the naked eye with an apparent visual magnitude of +4.89. Based upon an annual parallax shift of 12.44 mas, the distance to this star is . This is an A-type main sequence star with a stellar classification of A1 V. It has a high rate of rotation with a projected rotational velocity of 133 km/s.
This star has a stellar classification of F7 V, indicating that it is an F-type main-sequence star that is generating energy at its core through the thermonuclear fusion of hydrogen into helium. It is larger than the Sun, with 120% of the Sun's radius and 122% of the solar mass; as such, it shines nearly twice as brightly as the Sun. HD 219623 is around 1.2 billion years in age, with a projected rotational velocity of 5.5 km/s.
Alpha Lacertae, Latinized from α Lacertae, is a single white-hued star in the constellation of Lacerta, located 103 light years from the Sun. It is the brightest star in Lacerta with an apparent visual magnitude of 3.76. The star is moving closer to the Earth with a heliocentric radial velocity of −4.5 km/s. This is an ordinary A-type main-sequence star with a stellar classification of A1 V, which indicates it is generating energy through hydrogen fusion at its core.
Psi3 Aquarii, Latinized from ψ3 Aquarii, is the Bayer designation for a visual binary star system in the constellation of Aquarius. It has an apparent visual magnitude of 4.98, which is bright enough to be seen with the naked eye. Parallax measurements give a distance estimate of roughly . The main component of this system is an A-type main sequence star with a stellar classification of A0 V. Its companion is an 11th magnitude star 1.5 arcseconds from the primary.
Kepler-61b (also known by its Kepler Object of Interest designation KOI-1361.01) is a super-Earth exoplanet orbiting within parts of the habitable zone of the K-type main-sequence star Kepler-61. It is located about 1,100 light-years (338 parsecs) from Earth in the constellation of Cygnus. It was discovered in 2013 using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured, by NASA's Kepler spacecraft.
HD 143361 is a star in the southern constellation Norma. With an apparent visual magnitude of 9.20, this star is too dim to be seen with the naked eye. It is close enough to the Earth that its distance can be determined using parallax measurements, yielding a value of roughly . This is a G-type main sequence star with a stellar classification of G6 V. It has around 95% of the Sun's mass and is around 8.1 billion years old.
Pulsations are common among Lambda Boötis star and seem to be more common than on normal main sequence stars of the same spectral type. BD Phoenicis is an A-type main-sequence star with a spectral type of A1Va. Stellar evolution models indicate it has about double the solar mass and an age of about 800 million years, having completed 83% of its main sequence lifetime. It is radiating 21 times the Sun's luminosity from its photosphere at an effective temperature of .
This is an F-type main-sequence star with a stellar classification of F1 Vn, where the 'n' notation indicates nebulous lines due to rapid rotation. At the estimated age of 1.7 billion years old, it is spinning with a projected rotational velocity of 150 km/s and has sub-solar metallicity. The star has 1.5 times the mass of the Sun and is radiating 11 times the Sun's luminosity from its photosphere at an effective temperature of about 6,938 K.
HD 9446 is a star located about 164 light-years away in the constellation of Triangulum, near the southwestern constellation border with Pisces. This object can be viewed with binoculars or a telescope, but it is too faint to be seen with the naked eye at its apparent visual magnitude of 8.35. It is drifting further away from the Sun with a radial velocity of +21 km/s. This object is a G-type main sequence star with a stellar classification of G5V.
Kepler-442 is a K-type main-sequence star approximately 1,206 light years from Earth in the constellation Lyra. It is located within the field of vision of the Kepler spacecraft, the satellite that NASA's Kepler Mission used to detect planets that may be transiting their stars. On January 6, 2015, along with the notable stars of Kepler-438 and Kepler-440, it was announced that the star has an extrasolar planet (a super-Earth) orbiting within the habitable zone, named Kepler-442b.
Along with four other stars in this well-known asterism, Phecda forms a loose association of stars known as the Ursa Major moving group. Like the other stars in the group, it is a main sequence star, as the Sun is, although somewhat hotter, brighter and larger. Phecda is located in relatively close physical proximity to the prominent Mizar-Alcor star system. The two are separated by an estimated distance of ; much closer than the two are from the Sun.
HD 222155 is a star in the northern constellation of Andromeda. It is a yellow star that can be viewed with binoculars or a small telescope, but is too faint to be seen with the naked eye at an apparent visual magnitude of 7.1. The imaging survey in 2017 did not detected any stellar companions to HD 222155. This is an old main sequence star with a stellar classification of G0V; a star that is nearing an exhaustion of its hydrogen fuel.
WASP-46 is a G-type main-sequence star about 1240 light-years away. The star is older than Sun and is strongly depleted in heavy elements compared to Sun, having just 45% of solar abundance. Despite its advanced age, the star is rotating rapidly, being spun up by the tides raised by giant planet on close orbit. The star is displaying an excess ultraviolet emission associated with starspot activity, and suspected to be surrounded by dust and debris disk.
Although HD 93250 is known to be a binary star, individual spectra of the two components have never been observed, although they are thought to be very similar. The spectral type of HD 93250 has variously been given as O5, O6/7, O4, and O3. It has sometimes been classified as a main sequence star and sometimes as a giant star. The Galactic O-Star Spectroscopic Survey has used it as the standard star for the newly created O4 subgiant spectral type.
The absolute magnitude of this star is 5.25, indicating it would have been visible to the naked eye at that time. This is an ancient, thick disk population II star with an estimated age of twelve billion years. It is a G-type main-sequence star with a stellar classification of G8 V Fe-1.0, indicating an anomalous underabundance of iron in the stellar atmosphere. The star has 80% of the mass of the Sun and 88% of the Sun's radius.
HD 147018 c is a gas giant extrasolar planet which orbits the G-type main sequence star HD 147018, located approximately 140 light years away in the constellation Triangulum Australe. It has mass at least six and a half time more than Jupiter and orbits HD 147018 nearly twice the distance between the Earth and the Sun. This planet is eight times farther away than HD 147018 b. This planet was discovered on August 11, 2009 by radial velocity method.
The fainter star—Zeta2 Antliae—is 386 ± 5 light-years distant and of magnitude 5.9. Eta Antliae is another double composed of a yellow white star of spectral type F1V and magnitude 5.31, with a companion of magnitude 11.3. Theta Antliae is likewise double, most likely composed of an A-type main sequence star and a yellow giant. S Antliae is an eclipsing binary star system that varies in apparent magnitude from 6.27 to 6.83 over a period of 15.6 hours.
It is a red giant of spectral type K2III that is around 54 times the Sun's radius and 930 times its luminosity. Around 4 times as massive as the Sun, it spent much of its life as a main-sequence star of spectral type B5V. Lying to the south of the quadrilateral between Beta and Epsilon Corvi is the orange-hued 6 Corvi, an ageing giant star of spectral type K1III that is around 70 times as luminous as the Sun.
HD 50554 is a yellow-white main-sequence star [F8V] that currently fuse hydrogen in its core. Since the star is 7th magnitude, it is not visible to the unaided eye, but with binoculars or a telescope, it should be easy to see this star. The age of the star is only 10 million years older than our Sun. It is a population I star with metallicity of –0.07 dex [Fe/H] or 85% as much metals as the Sun.
U Hydrae is a semi-regular variable star with a deep red color, 528 light-years from Earth. It has a minimum magnitude of 6.6 and a maximum magnitude of 4.2; its period is 115 days. Hydra includes GJ 357, an M-type main sequence star located only 31 light-years from the Solar System. This star has three confirmed exoplanets in its orbit, one of which, GJ 357 d, is considered to be a "Super-Earth" within the circumstellar habitable zone.
HD 164509 primary star is a yellow main sequence star of spectral class G2, similar to the Sun. It is young and metal rich, having heavy elements abundance 160% of solar. Initially it was thought the system to comprise a single G5 class star, but in 2016 it was discovered the G2 primary is accompanied by the M-class red dwarf star at projected separation of 36.5 AU. The evidence for the stellar companion being on bound orbit was further fortified in 2017.
The inner pair form a double-lined spectroscopic binary system with an orbital period of 3.26 days and an eccentricity of 0.13. Both stars appear to be similar B-type main-sequence stars with stellar classifications of B4 V. The third component has an angular separation of 22.8 arc seconds from the inner pair, and most likely is a smaller B-type main sequence star of spectral type B9V. The system is relatively young, with an estimated age of around 50 million years.
Beta Canum Venaticorum (β Canum Venaticorum, abbreviated Beta CVn, β CVn), also named Chara , is a G-type main-sequence star in the northern constellation of Canes Venatici. At an apparent visual magnitude of 4.26, it is the second-brightest star in the constellation. Based upon an annual parallax shift of 118.49 mas, this star is distant from the Sun. Along with the brighter star Cor Caroli, the pair form the "southern dog" in this constellation that represents hunting dogs.
This object an A-type main-sequence star with a stellar classification of A2V. It is 448 million years old with a high rate of spin, showing a projected rotational velocity of 136 km/s. This star has 2.14 times the mass of the Sun and 2.6 times the Sun's radius. It is radiating 25 times the luminosity of the Sun from its outer envelope at an effective temperature of 7,951 K. The star appears to display a slight infrared excess.
Thus it did not show a pre-eruption rise in brightness. This is an interacting binary star system consisting of a white dwarf primary star and a main sequence star with a stellar classification of G8V. The orbit has a period of 0.33381379 days and an inclination of 88.2° to the line of sight to the Earth, resulting in an eclipsing binary. The nova eruption is believed to have been driven by mass transferred from the secondary star to the white dwarf.
The star has a relatively high proper motion, traversing the celestial sphere at a rate of per year. The stellar classification of 68 Draconis is F5 V, indicating that it is a main sequence star that is fusing hydrogen into helium at its core to generate energy. The star appears to be over-luminous for a member of its class, being 0.73 magnitudes brighter than expected. This may indicate that this is a binary system with an unresolved secondary component.
A telescope reveals it is formed by two yellowish stars of magnitudes 4.7 and 5.8 that are 0.9 arcseconds apart. The two stars orbit each other every 262 years and the orbital eccentricity is 0.74. The components are a magnitude 4.7 evolved giant star of spectral type G8III, and a magnitude 5.8 F-type main-sequence star of spectral type F8V. The former has exhausted the hydrogen at its core, causing it to expand to 8 times the Sun's radius.
The majority of the polarimetric signal is the result of the reflection of the light from one star off the other (and vice versa). The two stars in Spica were the first ever to have their reflectivity (or geometric albedo) measured. The geometric albedos of Spica A and B are, respectively, 3.61 percent and 1.36 percent, values that are low compared to planets. The MK spectral classification of Spica is typically considered to be an early B-type main sequence star.
In about 328,000 years from now, the star will make its closest approach at a distance of around . This is a solar analog, which means its measured properties are similar to those of the Sun. However, it is much older than the Sun with an estimated age of around 8.1 billion years. The spectrum matches a stellar classification of G1 V, indicating this is an ordinary G-type main- sequence star that is generating energy through hydrogen fusion at its core.
Delta Tucanae A is a main sequence star of spectral type B9.5V and an apparent magnitude of 4.49. The companion has an apparent magnitude of 9.3. The Kappa Tucanae system shines with a combined apparent magnitude of 4.25, and is located around 68 light-years from the Solar System. The brighter component is a yellowish star, known as Kappa Tucanae A with an apparent magnitude of 5.33 and spectral type F6V, while the fainter lies 5 arcseconds to the northwest.
Lambda1 is itself a binary star, with two components—a yellow-white star of spectral type F7IV-V and an apparent magnitude of 6.22, and a yellow main sequence star of spectral type G1V and an apparent magnitude of 7.28. The system is 186 light-years distant. Lambda2 is an orange subgiant of spectral type K2III that is expanding and cooling and has left the main sequence. Of apparent magnitude 5.46, it is approximately 220 light-years distant from Earth.
This is a B-type main sequence star with a stellar classification of B9.5 Vne. The 'n' suffix indicates the spectrum shows "nebulous" absorption lines due to rapid rotation, while the 'e' means this is a Be star that displays Balmer series emission lines. With an estimated age of 195 million years, it is about 75% of the way through its life span on the main sequence. The star is rotating with a projected rotational velocity of 191 km/s.
LS 5039 is a binary system in the constellation of Scutum. It has an apparent magnitude of 11.27, and it is about 8,200 light-years away. LS 5039 consists of a massive O-type main-sequence star, and a compact object (likely a black hole) that emits HE (high energy) and VHE (very high energy) gamma rays. It is one of the only three known star systems of this kind, together with LS I +61 303 and PSR B1259-63.
Based upon proper motion variation, this is an astrometric binary system with high likelihood (99.8%). The visible component has a stellar classification of F0 Vn, indicating it is a F-type main-sequence star with "nebulous" lines due to rapid rotation. It is a Delta Scuti variable star with a period of 0.0960 days and an amplitude of 0.020 in magnitude. With 2.4 times the mass of the Sun it is spinning with a high projected rotational velocity of 133 km/s.
29 Cancri is a star in the zodiac constellation of Cancer, located 370 light years from the Sun. It is just visible to the naked eye as a dim, white-hued star with an apparent visual magnitude of 5.94. The star is situated near the ecliptic, which means it is subject to lunar occultations. This is an A-type main-sequence star with a stellar classification of A5 V, which indicates it is generating energy through hydrogen fusion at its core.
37 Cancri is a star in the zodiac constellation of Cancer. It is a challenge to view with the naked eye, having an apparent magnitude of 6.54. The star is moving away from the Earth with a heliocentric radial velocity of +22 km/s, having come as close as some 2.7 million years ago. This is an ordinary A-type main-sequence star with a stellar classification of A1 V, which indicates it is generating energy through hydrogen fusion at its core.
This is an F-type main-sequence star with a stellar classification of F0 V. It is catalogued a low amplitude Delta Scuti variable with a primary period of 0.273 days. It was originally classified, tentatively, as an RR Lyrae variable of type 'c'. 64 Eridani is spinning rapidly with a projected rotational velocity of 212 km/s. This is giving the star an oblate shape with an equatorial bulge; its equatorial radius is 8% larger than its polar radius.
The visible component has a stellar classification of , which indicates it has the spectrum of an F-type main-sequence star with mild underabundances of iron and methylidyne. It is 1.4 billion years old with 1.3 times the mass of the Sun and 1.5 times the Sun's radius. The star is radiating 3.87 times the luminosity of the Sun from its photosphere at an effective temperature of 6,719 K. The system has been detected as a source of X-ray emission.
Hierarchy of orbits in the 65 Ursae Majoris system The central pair of stars are both A-type main-sequence stars. These are relatively bright, white-colored stars that typically have masses from to . 65 Ursae Majoris Aa1 and Aa2 both have relatively low masses for an A-type main sequence star and have spectral types of A7V. Both components periodically pass in front of each other while orbiting, so they form an eclipsing binary with the variable star designation DN Ursae Majoris.
Delta1 Canis Minoris, Latinized from δ1 Canis Minoris, is a solitary, yellow- white hued star in the constellation Canis Minor. It is faintly visible to the naked eye with an apparent visual magnitude of +5.25. Based upon an annual parallax shift of 4.29 mas as seen from Earth, this star is located roughly 760 light years from the Sun. Houk and Swift (1999) list a stellar classification of F0 V for Delta1 Canis Minoris, indicating it is an F-type main-sequence star.
The brighter member of the system, designated component A, is an A-type main-sequence star with a stellar classification of A2 V. It is around 162 million years old with a high rate of spin, showing a projected rotational velocity of 183 km/s. Estimates of the mass of the star range from 1.7 up to 2.73 times the mass of the Sun. It is radiating 96 times the Sun's luminosity from its photosphere at an effective temperature of 8,974 K.
It oscillates with multiple, non-radial pulsation cycles and a dominant cycle of 6.8 minutes. The spectrum shows peculiar features caused by chemical stratification of the outer atmosphere. It displays a moderate deficiency of carbon, nitrogen and oxygen, while there is an overabundance of chromium (Cr). The stellar classification of A7 Vp SrCrEu indicates that this is a main sequence star with enhanced levels of strontium (Sr), chromium, and europium (Eu) in its atmosphere (compared to a typical star like the Sun).
The brighter star, component A, has a visual magnitude of 6.6, while the secondary, component B, is magnitude 7.0. As of 2000, the pair had an angular separation of 0.737 arc seconds along a position angle of 14.0°. Component A is a blue-white hued B-type main sequence star with a stellar classification of B9.5 V. It has 2.8 times the mass of the Sun and radiates 94 times the solar luminosity from its photosphere at an effective temperature of 10,351 K.
According to Fuhrmann and Chini (2015) this is an astrometric binary system, although Eggleton and Tokovinin (2008) deemed it to be a single star. The visible component is an ordinary F-type main-sequence star with a stellar classification of F5V. It is around 1.6 billion years old with 1.25 times the mass of the Sun and 1.40 times the Sun's radius. The star is radiating three times the luminosity of the Sun from its photosphere at an effective temperature of 6,395 K.
The star is radiating 173 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,688 K. The fainter component at magnitude 6.57 is a double-lined spectroscopic binary with an orbital period of 7.33 days and an eccentricity of 0.26. The primary member of this pair is an A-type main- sequence star with a stellar classification of A9V. It is a metallic-lined Am star with 2.9 times the radius of the Sun.
This object is an A-type main-sequence star with a stellar classification of A0.5Va. It is 206 million years old and is rotating with a projected rotational velocity of 83 km/s. The star has 2.25 times the mass of the Sun and 2.87 times the Sun's radius. It is radiating 28 times the luminosity of the Sun from its photosphere at an effective temperature of 7,836 K. Nu Tauri has a magnitude 9.21 visual companion at an angular separation .
Zeta Corvi, Latinized from ζ Corvi, is a star in the constellation Corvus. It is a blue-white main sequence star of apparent magnitude 5.21. Located around 420 light-years distant, it shines with a luminosity approximately 154 times that of the Sun and has a surface temperature of 10,695 K. It is a Be star, the presence of hydrogen emission lines in its spectrum indicating it has a circumstellar disk. It is separated by 7 arcminutes from the star HR 4691.
The primary is an F-type main sequence star with a stellar classification of F4 Vw, where the w indicates relatively weak metallic features in the ultraviolet spectrum. This star has 134% of the Sun's mass, but only 97% of the solar radius. It is spinning with a projected rotational velocity of 31.7 km/s, and is around 1.2 billion years old. The effective temperature of the outer atmosphere is 6,615 K, giving it the yellow-white hue of an F-type star.
This star shows periodic radial velocity variations that can be best explained as a spectroscopic binary system. The visible component is an A-type main sequence star with a stellar classification of A3 V. It has twice the mass of the Sun and shines with about 12 times the Sun's luminosity from its outer atmosphere at an effective temperature of 9,206 K. The star is an estimated 237 million years old and is spinning with a projected rotational velocity of 78 km/s.
Mu Telescopii (μ Telescopii) is a yellow-white hued star in the southern constellation of Telescopium. With an apparent visual magnitude of +6.30, it is near the limit of stars that can be viewed with the naked eye. Based upon an annual parallax shift of 20.18 mas as seen from Earth, it is located around 162 light years from the Sun. This is an F-type main sequence star with a stellar classification of F5 V. It is chromospherically active.
Epsilon Trianguli, Latinized from ε Trianguli, is a binary star system in the northern constellation of Triangulum. Based upon measurement of its trigonometric parallax, it is approximately 390 light years from Earth. The primary component is an A-type main sequence star with a stellar classification of A2 V, an apparent magnitude of +5.50 and an estimated age of 600 million years. It has 2.75 times the mass of the Sun and is spinning with a projected rotational velocity of 107 km/s.
Parallax measurements yield a distance estimate of around 730 light years from the Sun. The system is moving further away from the Earth with a heliocentric radial velocity of +18.7 km/s. This is a double-lined spectroscopic binary system with an orbital period of 260 days and an eccentricity of 0.024. The spectrum reveals the pair to consist of an A-type main-sequence star with a stellar classification of A1 V, and a red giant with a class of M6III.
This is a young A-type main-sequence star with a stellar classification of A1V. It is about 40 million years old with a high rate of spin, showing a projected rotational velocity of 196 km/s. The star has double the mass of the Sun. It is radiating 19 times the Sun's luminosity from its photosphere at an effective temperature of 8,790 K. 49 Ceti displays a significant infrared excess, which is a characteristic of a debris disk orbiting the star.
This occurs because centripetal acceleration from the orbital motion resists the gravitational pull of the star only in the radial direction, but the cloud remains free to collapse in the vertical direction. The outcome is the formation of a thin disc supported by gas pressure in the vertical direction. The initial collapse takes about 100,000 years. After that time the star reaches a surface temperature similar to that of a main sequence star of the same mass and becomes visible.
This is an F-type main-sequence star with a stellar classification of F5 V. This indicates that, at the age of 2.2 billion years, it is still generating energy through hydrogen fusion at its core. It is radiating 7.5 times the Sun's luminosity from its photosphere at an effective temperature of 6,471 K. The star has an estimated 1.4 times the mass of the Sun and is spinning with a moderately high projected rotational velocity of 44.4 km/s.
The system appears to be moving closer to the Sun with a radial velocity of around −10 km/s. Eta Trianguli Australis is a B-type main-sequence star with a stellar classification of B7 V. Although it has been classified as a B7 IVe Be subgiant star in the past, Jaschek and Jaschek (1992) found no trace of emission in the spectrum. Grady et al. (1989) reported only "weak or narrow double-peaked Hα emission, but no emission at Hβ".
38 Virginis is an F-type main sequence star that is approximately 118% the mass of and 145% the radius of the Sun. It has a temperature of 6557 K and is about 1.9 billion years old. In comparison, the Sun is about 4.6 billion years old and has a temperature of 5778 K. The star is metal-rich, with a metallicity ([Fe/H]) of 0.07 dex, or 117% the solar amount. Its luminosity () is 3.48 times that of the Sun.
Theta1 Orionis D (θ1 Orionis D) is a member of the Trapezium open cluster that lies within the Orion Nebula. It is a B class blue main sequence star with several faint companions. θ1 Orionis consists of multiple components, primarily the four stars of the Trapezium cluster (A, B, C, and D) all within one arc-minute of each other. θ2 Orionis is a more distant grouping of three main stars plus several fainter companions, 1-2 arc-minutes from θ1.
Muphrid and Arcturus lie only 3.3 light-years away from each other. Viewed from Arcturus, Muphrid would have a visual magnitude of -2½, while Arcturus would be around visual magnitude -4½ when seen from Muphrid. Marking the herdsman's head is Beta Boötis, or Nekkar, a yellow giant of magnitude 3.5 and spectral type G8IIIa. Like Arcturus, it has expanded and cooled off the main sequence—likely to have lived most of its stellar life as a blue-white B-type main sequence star.
Epsilon Boötis, also known as Izar or Pulcherrima, is a close triple star popular with amateur astronomers and the most prominent binary star in Boötes. The primary is a yellow- or orange- hued magnitude 2.5 giant star, the secondary is a magnitude 4.6 blue-hued main-sequence star, and the tertiary is a magnitude 12.0 star. The system is 210 light-years away. The name "Izar" comes from the Arabic word for "girdle" or "loincloth", referring to its location in the constellation.
HD 5388 b (also known as HIP 4311 b) was thought to be an extrasolar planet orbiting the F-type main sequence star HD 5388, located approximately 175 light years away in the constellation Phoenix. It takes over two years to orbit the star at a semimajor axis of 1.76 AU with an eccentricity of 0.40. It was announced on October 19, 2009, together with 29 other planets. This planet has been disproved and shown to be a brown dwarf.
This is a probable single-lined spectroscopic binary star system. The visible component has a stellar classification of F3 V or F3 IV, indicating it is either an F-type main-sequence star or a somewhat more evolved subgiant star, respectively. It has an estimated 1.3 times the mass of the Sun and about 1.3 times the Sun's radius. The star is 1.75 billion years old and has a high rate of spin with a projected rotational velocity of around 97.5 km/s.
BD-08°2823 c (also known as HIP 49067 c) is an extrasolar planet which orbits the K-type main sequence star BD-08°2823, located approximately 135 light years away in the constellation Sextans. This planet has at least one-thirds the mass of Jupiter and takes 7.8 months to orbit the star at a semimajor axis of 0.68 AU. This planet was detected by HARPS on October 19, 2009, together with 29 other planets, including BD-08°2823 b.
HD 111456 is a nucleus cluster member of the Ursa Major Moving Group, a set of stars that are moving through space with a similar heading and velocity. Six other stars in the nucleus form prominent members of the Big Dipper asterism. The stellar classification for this star is F7 V, indicating that it is an ordinary F-type main-sequence star. It is young, around 300−400 million years of age, and is spinning with a relatively high projected rotational velocity of 41.5 km/s.
Houk (1978) categorizes the visible component (Beta² Sagittarii A) as an F-type main-sequence star with a stellar classification of F2/3 V. However, Malaroda (1975) lists it as an F-type giant star. It is spinning rapidly with a projected rotational velocity of 155 km/s. This is giving it an oblate shape with an equatorial bulge that is 22% larger than the polar radius. Beta² Sagittarii has an estimated 1.4 times the mass of the Sun and is around 933 million years old.
Kepler-90h (also known by its Kepler Object of Interest designation KOI-351.01) is an exoplanet orbiting within the habitable zone of the early G-type main sequence star Kepler-90, the outermost of eight such planets discovered by NASA's Kepler spacecraft. It is located about 2,840 light-years (870 parsecs), from Earth in the constellation Draco. The exoplanet was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured.
This object is an Ap star with a stellar classification of ApSrEuCr, displaying strong abundance anomalies of the elements strontium, europium, and chromium. Abt and Morrell (1995) found a class of , showing further an A-type main-sequence star with a Ca II line (single-ionized calcium) having both sharp and broad components. It is an Alpha2 Canum Venaticorum variable, with its brightness ranging from magnitude 4.44 down to 4.51 over a period of 2.99 days. A strong magnetic field has been measured on the surface.
Xi Virginis (ξ Vir, ξ Virginis) is a solitary star in the zodiac constellation of Virgo. It is bright enough to be seen with the naked eye, having an apparent visual magnitude of 4.83. The distance to this star is about 122 light years, as determined from parallax readings. Xi Virginis is an A-type main sequence star with a stellar classification of A4 V. It has an estimated age of 480 million years and is spinning rapidly with a projected rotational velocity of 130 km/s.
The orbit of the two stars has been calculated from the secondary changing its position relative to the primary. The two orbit each other every 31.6 years with an angular semimajor axis of 0.22 arcseconds and an eccentricity of 0.7560. The combined spectrum of 20 Persei matches that of an F-type main- sequence star, and the two stars are thought to have equal masses, 1.5 times that of the Sun. A ninth-magnitude star, designated 20 Persei C, may be associated with the pair.
59 Persei is a suspected astrometric binary star system in the northern constellation of Perseus. It is visible to the naked eye as a dim, white-hued star with an apparent magnitude of 5.30. The star is located around 256 light years distant from the Sun, based on parallax, and is drifting further away with a radial velocity of +13 km/s. This is an ordinary A-type main-sequence star with a stellar classification of A1Vn, a star that is fusing its core hydrogen.
It has also been described as a neon star, due to the very high relative levels of that element. It has been stripped of its outer hydrogen layers after it expanded away from the main sequence. It is thought to have originated as a main sequence star with around , expanded when it exhausted its core hydrogen, and now only remains, highly inflated and giving the appearance of a supergiant star. Other estimates give higher masses, as much as and at the known inclination of 50°.
This is a B-type main-sequence star with a stellar classification of B8 V; a massive star that is generating energy through hydrogen fusion at its core. It has 3.44 times the mass of the Sun and about 3 times the Sun's radius. The star is about 197 million years old and is spinning rapidly with a projected rotational velocity of 288 km/s. It is radiating roughly 193 times the Sun's luminosity from its photosphere at an effective temperature of 12,246 K.
The primary member of the system, component A, is a yellow-white hued F-type main-sequence star with a stellar classification of F9.5V. It is an estimated 5.7 billion years old and is spinning with a rotation period of 14.3 days. The star has a short magnetic activity cycle that averages around 3.5 years. A second cycle appears to vary over time, lasting 13.7 years at the start of observations then decreasing to 8.6 years over a span of 34 years of measurement.
FF Aql is a possible quadruple star system. Analysis of its spectrum shows that it is a spectroscopic binary system with the fainter companion calculated to be a main sequence star of spectral type A9V to F3V, orbiting every 3.92 years. A third star, revealed by speckle interferometry, is likely to be a cooler star that has evolved off the main sequence. A fourth star, that is of magnitude 11.4 and located 6 arcseconds away, is unlikely to be a member of the system.
HD 104067 b is an extrasolar planet which orbits the K-type main sequence star HD 104067, located approximately 68 light years away in the constellation Corvus. This planet has at least one-sixth the mass of Jupiter and takes over one-sevenths of a year to orbit the star at a semimajor axis of 0.26 AU. This planet was detected by HARPS on October 19, 2009, together with 29 other planets. It is also the first planet to be discovered in this constellation.
HD 222095 is a single star in the southern constellation of Phoenix, near the western constellation border with Grus. It has a white hue and is visible to the naked eye with an apparent visual magnitude of 4.74. The star is located at a distance of is approximately 200 light years based on parallax, and it is drifting further away with a radial velocity of +3.4 km/s. This object is an A-type main-sequence star with a stellar classification of A1/2V.
Based upon this, the primary has a mass around 138% of the Sun, 155% of the Sun's radius, and shines with three times the Sun's luminosity. The smaller secondary component is also larger than the Sun, with 124% of the Sun's mass, 131% of the radius of the Sun, and has 186% of the Sun's luminosity. The stellar classification of the primary is F9 V, which suggests it is an F-type main sequence star. The pair have an estimated age of just over a billion years.
HAT-P-13, also known as GSC 03416-00543, is a G-type main sequence star approximately 811 light-years away in the constellation Ursa Major. In 2009 it was discovered that this star is orbited by two massive planets, the innermost of which transits the star. This was the first known example of an extrasolar transiting planet with an additional planet in the same system. In 2015, a spectroscopic study have revealed a very strong starspot activity of the HAT-P-13 star.
Anybody attempting to view the object is likely to instead see the Asterope pair as a single elongated form of magnitude 5.6. Based upon an annual parallax shift of , this star is located 444 light years away from the Sun. It is moving further from the Earth with a heliocentric radial velocity of +7 km/s. This is an ordinary A-type main-sequence star with a stellar classification of A0 Vn. The 'n' suffix indicates the spectrum displays "nebulous" absorption lines due to rapid rotation.
A main sequence star supported by thermal pressure can expand and cool which automatically regulates the increase in thermal energy. However, degeneracy pressure is independent of temperature; white dwarfs are unable to regulate temperature in the manner of normal stars, so they are vulnerable to runaway fusion reactions. The flare accelerates dramatically, in part due to the Rayleigh–Taylor instability and interactions with turbulence. It is still a matter of considerable debate whether this flare transforms into a supersonic detonation from a subsonic deflagration.
Both stars are surrounded by a large envelope of in-falling material left over from the original cloud that formed the system. Both stars are emitting jets of material, that of the Herbig Ae/Be star being much larger—11.7 light-years long. Meanwhile, FS Canis Majoris is another star with infra-red emissions indicating a compact shell of dust, but it appears to be a main-sequence star that has absorbed material from a companion. These stars are thought to be significant contributors to interstellar dust.
While both have a similar proper motion and parallax, there's still no proof that the pair is gravitationally bound. The primary component is HD 5789, a B-type main-sequence star with a stellar classification of B9.5Vnn (λ Boo), where the 'n' indicates "nebulous" lines due to rapid rotation. Abt and Morrell (1995) listed it as a Lambda Boötis star, although this is disputed. It has 2.7 times the mass of the Sun and is spinning rapidly with a projected rotational velocity of 249 km/s.
Exocomets beyond the Solar System have also been detected and may be common in the Milky Way. The first exocomet system detected was around Beta Pictoris, a very young A-type main-sequence star, in 1987. A total of 11 such exocomet systems have been identified , using the absorption spectrum caused by the large clouds of gas emitted by comets when passing close to their star. For ten years the Kepler Space Telescope was responsible for searching for planets and other forms outside of the solar system.
The latter was found to have a temperature and luminosity well below the stellar range. Its near-infrared spectrum clearly exhibited a methane absorption band at 2 micrometres, a feature that had previously only been observed in the atmospheres of giant planets and that of Saturn's moon Titan. Methane absorption is not expected at any temperature of a main-sequence star. This discovery helped to establish yet another spectral class even cooler than L dwarfs, known as "T dwarfs", for which Gliese 229B is the prototype.
It has four times the mass of the Sun and has expanded to 32 times the Sun's radius. The star is radiating 531 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,868 K. The secondary is a suspected binary of unknown period, with its components having estimated masses equal to 2.4 and 1.0 times the mass of the Sun. The more massive member of the pair has an estimated spectral class of A2V, matching an A-type main-sequence star.
Kappa Piscium has an apparent magnitude of 4.87 at maximum brightness and 4.95 at minimum brightness, while the visual companions have apparent magnitudes of 9.96 and 11.20. This is an A-type main-sequence star with a stellar classification of . The suffix designation indicates it is a "chemically peculiar" Ap star that displays abnormal abundances of silicon, strontium, and chromium. It is an Alpha2 Canum Venaticorum variable with a weak active magnetic field that causes it to fluctuate by 0.01 to 0.1 in magnitude as it rotates.
HD 108541, also known by its Bayer designation u Centauri is a star located in the constellation Centaurus, It is also known as HR 4748. The apparent magnitude of the star is about 5.4, meaning it is only visible to the naked eye under excellent viewing conditions. Its distance is about 440 light-years (140 parsecs), based on its parallax measured by the Hipparcos astrometry satellite. The spectral type of HD 108541 is B8/9V, meaning it is a late B-type main sequence star.
The primary, component A, appears to be a normal F-type main sequence star with a stellar classification of F5 V. However, Malaroda (1975) assigned it a classification of F4 IV, which would suggest it is a more evolved subgiant star. It is estimated to have 121% of the Sun's mass and around 150% of the radius of the Sun. With an age of about 2.1 billion years, it is radiating 7.6 times the solar luminosity from its outer atmosphere at an effective temperature of 6,527 K.
The lack of significant ultraviolet emission appears to rule out a white dwarf companion. Instead, the secondary may consist of a binary pair of low mass dwarfs. The visible component is an F-type main-sequence star with a stellar classification of F8 V. The spectrum of the star is unusual for its near absence of lithium. With an estimated age of about three billion years, it has 1.4 times the mass of the Sun and is spinning with a projected rotational velocity of 6 km/s.
HD 87883 b is an extrasolar planet which orbits the K-type main sequence star HD 87883, located approximately 59 light years away in the constellation Leo Minor. It is a long-period planet, taking seven and a half years to orbit the star at the average distance of 3.60 AU. However, this planet orbits in a very eccentric path, which ranges distance from as close as 1.69 AU to as far as 5.51 AU. This planet was detected by radial velocity method on August 13, 2009.
The stellar classification for this star is G2/3 IV/V, which indicates the spectrum displays mixed traits of a G-type main- sequence star and a more evolved subgiant star. It is 2.6 billion years old and is spinning with a projected rotational velocity of 8.75 km/s. The star has 1.45 times the mass of the Sun and 2.8 times the Sun's radius. It is radiating 13 times the luminosity of the Sun from its photosphere at an effective temperature of 5,926 K.
39 Tauri is the Flamsteed designation for an unresolved binary star in the northern constellation of Taurus. It has an apparent visual magnitude of 5.90, so, according to the Bortle scale, it is faintly visible from suburban skies at night. Measurements made with the Hipparcos spacecraft show an annual parallax shift of 0.05904″, which is equivalent to a distance of around from the Sun. A stellar classification of G5 V matches that of a G-type main sequence star; the type of the secondary component is unknown.
This object is a G-type main-sequence star with a stellar classification of G3VFe0.5, where the suffix notation indicates a mild overabundance of iron. It is roughly two billion years old and is spinning with a projected rotational velocity of 5 km/s. This is a solar-type star with 5% greater mass compared to the Sun and 1.24 times the Sun's radius. The star is radiating 1.19 times the luminosity of the Sun from its photosphere at an effective temperature of 5,386 K.
This is an A-type main-sequence star with a stellar classification of A1VmA3, indicating it has the spectrum of an A1 class star with the metal-lines of an A3 star. It is an estimated 212 million years old with a projected rotational velocity of 81 km/s. The star has 2.15 times the mass of the Sun with 1.70 times the Sun's radius. It is radiating 21.6 times the Sun's luminosity from its photosphere at an effective temperature of around 9,622 K.
"The team has discovered the most Earthlike planet yet", said Michael Turner, assistant director for the mathematical and physical sciences directorate at the National Science Foundation, which supported the work. At the time of discovery, with 5.5 Earth masses, the planet was less massive than the previous candidate for lowest-mass exoplanet around a main-sequence star, the 7.5 Earth mass Gliese 876 d. Since 2013, many Earth-sized or smaller planets around main-sequence stars have been detected by the Kepler spacecraft and others.
This is a G-type main sequence star with a stellar classification of G1 V. In terms of composition it is similar to the Sun, while the mass and radius are slightly larger. It is 73% more luminous than the Sun and radiates this energy from its outer atmosphere at an effective temperature of . At this heat, the star glows with the yellow hue of a G-type star. It has a low level of surface activity and is a candidate Maunder minimum analog.
The outer pair has an orbital period of 1,598 years with an eccentricity of 0.536. The magnitude 6.02 primary, component A, is itself a binary system consisting of two stars of similar mass, roughly 1.5 times the mass of the Sun each, with an orbital period of . It has a stellar classification of F5 V, matching an F-type main-sequence star. As of 2017, component B is a magnitude 9.50 star at an angular separation of from the primary along a position angle of 285°.
It is moving further from the Earth with a heliocentric radial velocity of +6 km/s. This is a B-type main sequence star with a stellar classification of B9.5 V. It is 257 million years old and is spinning with a projected rotational velocity of 33 km/s. The star has more than double the mass of the Sun and around 2.2 times the Sun's radius. It is radiating 40 times the Sun's luminosity from its photosphere at an effective temperature of 10,913 K.
It is receding from the Earth with a heliocentric radial velocity of +9.5 km/s, and is a member of the IC 2391 moving group. This is an ordinary G-type main sequence star with a stellar classification of G8 V. Similar to the Sun, it has 1.04 times the mass and 0.99 times the Sun's radius. It is 1.4 billion years old with a leisurely rotation rate, showing a projected rotational velocity of 4 km/s. The atmospheric metallicity is higher than solar.
It is moving closer to the Earth with a heliocentric radial velocity of −13 km/s. This is a B-type main-sequence star with a stellar classification of B9 V. It was classed as a Be star by Arne Sletteback in 1982, indicating it has ionized circumstellar gas. The star is spinning rapidly, showing a projected rotational velocity of 259 km/s, and is being viewed almost equator-on. It has 3.6 times the mass of the Sun and 3 times the Sun's radius.
The naked-eye component A is a single- lined spectroscopic binary. Only the signature of an F-type main sequence star can be seen in the spectrum, but the periodic doppler shift of the absorption lines demonstrates that there is a hidden companion in a 391.7-day orbit. Four other companions to 9 Aurigae are listed in multiple star catalogs, all thought to be common proper motion companions at the same distance from us as 9 Aurigae. The closest companion is a 12th-magnitude red dwarf away.
The binary nature of the star was discovered by American astronomer Sherburne Wesley Burnham at Lick Observatory in 1889. The pair orbit each other over a period of 74 years with a high eccentricity of 0.8. The magnitude 5.26 primary, designated component A, is an A-type main-sequence star based on a stellar classification of A1V or A2V, although it may have already left the main sequence. It was identified as a candidate Lambda Boötis star, but this was ruled out by Paunzen et al.
It is moving further from the Earth with a heliocentric radial velocity of +10 km/s. This is a B-type main-sequence star with a stellar classification of B9 Ve, where the 'e' notation indicates this is a Be star. The stellar spectrum of 18 And displays an emission line in the hydrogen Brackett series due to a dense gaseous circumstellar envelope. The star is spinning rapidly with a projected rotational velocity of 183 km/s and has about three times the mass of the Sun.
5 Andromedae is moving closer to the Sun with a radial velocity of −2.6 km/s. It has a relatively high proper motion, advancing across the celestial sphere at the rate of 0.201 arc seconds per year. This is an ordinary F-type main-sequence star with a stellar classification of F5 V. It is estimated to be 2.3 billion years old and is spinning with a projected rotational velocity of 9.7 km/s. The star has 1.39 times the mass of the Sun.
50 Boötis is a single star located 275 light years away from the Sun in the northern constellation of Boötes. It is visible to the naked eye as a dim, blue-white hued star with an apparent visual magnitude of 5.38. The object is moving closer to the Earth with a heliocentric radial velocity of −9 km/s. This is a B-type main-sequence star with a stellar classification of B9 Vn, where the 'n' notation indicates "nebulous" lines due to rapid rotation.
In 2015, H. Bouy and J. Alves suggested that it is a member of the newly-discovered Taurion OB association. This object is a B-type main-sequence star with a stellar classification of B5Vn, where the 'n' suffix indicates "nebulous" (broad) lines due to rapid rotation. It has a projected rotational velocity of 285 km/s, compared to a critical velocity of ; the polar axis is inclined by . This is a known Be star that began behaving as a normal star in November, 1982.
The disk has a radius of about 370 astronomical units (au) with about 40 Earth masses of dust in the disk. V4046 Sagittarii is one of four pre-main-sequence star systems within 100 parsecs with protoplanetary disks, the others being TW Hydrae, HD 141569, and 49 Ceti. The two stars are still accreting matter from the disk, and gas giant planets may be forming in the disk as well. The red dwarf binary GSC 07396-00759 is separated about 2.82″ from V4046 Sagittarii.
The radial velocity is poorly constrained, but the star appears to be drifting further away from the Sun at the rate of around 5 km/s. It is a member of the Sirius supercluster of co-moving stars. This is an Am star or metallic-line star with a stellar classification of F0V, indicating it is a F-type main-sequence star that is generating energy by core hydrogen fusion. It is an estimated 467 million years old and has 1.62 times the mass of the Sun.
As the hydrogen fuel at the core of the progenitor of IK Pegasi B was consumed, it evolved into a red giant. The inner core contracted until hydrogen burning commenced in a shell surrounding the helium core. To compensate for the temperature increase, the outer envelope expanded to many times the radius it possessed as a main sequence star. When the core reached a temperature and density where helium could start to undergo fusion this star contracted and became what is termed a horizontal branch star.
The star is a probable (93% chance) member of the Sco OB2 moving group of stars. This is a B-type main-sequence star with a stellar classification of B3V, which indicates it is engaged in core hydrogen fusion to generate energy. The object has been used as a "standard star" in several photometric systems, and it appears to be non-variable. It is an estimated 18 million years old with a high rate of spin, showing a projected rotational velocity of 129 km/s.
The primary, component A, is a G-type main- sequence star with a stellar classification of G9VCN+1. The suffix notation indicates an overabundance of the cyano radical in the spectrum. Houk and Swift (1999) found a class of G8IV, suggesting it is instead a more evolved subgiant star. It is around seven billion years old and is spinning slowly with a projected rotational velocity of 1.5 km/s. The star has 1.1 times the mass of the Sun and 2.2 times the Sun's radius.
This is a B-type main-sequence star with a stellar classification of B2.5 V, per Lesh (1968). Slettebak (1982) found a class of B2 IV(e), which would suggest this is a more evolved subgiant star. It is a Be star, which means the spectrum displays emission lines due a disk of ejected gas in a Keplerian orbit around the star. The star displays short-term variability with two or more periods, and is classified as an SX Arietis variable by Samus et al. (2017).
Kepler-47 is a binary star system located about away from Earth. The binary system is composed of a G-type main sequence star (Kepler-47A) and a red dwarf star (Kepler-47B). The stars orbit each other around their barycenter, or center of mass between them, completing one full orbit every 7.45 days. The stars orbit their barycenter from a distance of about 0.084 AU. The stars have 104% and 35% of the Sun's mass, and 96% and 35% of the Sun's radius, respectively.
This is an F-type main sequence star with a stellar classification of F2 V. It is a suspected variable star that ranges in magnitude from a maximum of 5.35 to a minimum of 5.44 magnitude. The star is a source of X-ray emission with a luminosity of . It is 778 million years old and is spinning with a projected rotational velocity of 60.1 km/s. The star has 1.3 times the mass of the Sun and about 1.1 times the Sun's radius.
Hummel et al. (1996) gave the primary component, θ Aql A, an estimated mass of 3.6 solar, a radius 4.8 the Sun's, and 278 the luminosity of the Sun. For the secondary component, θ Aql B, they give the corresponding parameters as 2.9 times the mass, 2.4 times the radius and 68 times the luminosity of the Sun. Based upon their estimated parameters, Kaler (2008) suggests that θ Aql A is actually a subgiant star, while θ Aql B is a main sequence star.
This star has a stellar classification of A1 V, indicating it is an A-type main-sequence star that is generating energy through hydrogen fusion at its core. The spectrum displays an overabundance of silicon in the atmosphere, but the abundance of iron is the same as in the Sun. The star has 2.2 times the mass of the Sun and 2.2 times the Sun's radius. It is around a half billion years old and is spinning rapidly with a projected rotational velocity of 127 km/s.
CoRoT-2 is a yellow dwarf main sequence star a little cooler than the Sun. This star is located approximately 700 light-years away in the constellation of Aquila. The apparent magnitude of this star is 12, which means it is not visible to the naked eye but can be seen with a medium-sized amateur telescope on a clear dark night. It has a true physical companion, 2MASS J19270636+0122577, with a spectral type of K9, as earlier hypothesized by Alonso et al.
The 4.46 magnitude primary component is a Be star with a stellar classification of B7 Ve, indicating that it is a B-type main sequence star that shows prominent emission lines of hydrogen in its spectrum. These emission lines come from a flattened decretion disk of hot gas that is orbiting the host star. The star is rotating rapidly with a projected rotational velocity of 75 km/s. The pole of the star is inclined around 20° to the line of sight from the Earth.
This is an A-type main sequence star with a stellar classification of A7 V. Nu Arietis has an estimated 2.4 times the mass of the Sun and about 1.8 times the Sun's radius. The star is radiating 63.5 times the Sun's luminosity from its photosphere at an effective temperature of around 8,000 K. It is roughly 621 million years old and is spinning with a projected rotational velocity of 133 km/s. A close companion was discovered in 2016 using the direct spectral detection method.
Xi2 Capricorni (ξ2 Capricorni) is a yellow-white hued star in the southern constellation of Capricornus. It is dimly visible to the naked eye on a dark night, having an apparent visual magnitude of +5.83. Based upon an annual parallax shift of 36.10 mas as seen from Earth, this system is located 90 light years from the Sun. This is an F-type main-sequence star with a stellar classification of , where the suffix notation indicates the spectrum displays a mild underabundance of iron.
This is an ordinary F-type main-sequence star with a stellar classification of F4V. It is around 1.3 billion years old and retains a relatively high projected rotational velocity of 60 km/s. The star has 1.45 times the mass of the Sun and 1.67 times the Sun's radius. It is radiating 4.8 times the luminosity of the Sun from its photosphere at an effective temperature of 6,699 K. The star is the most likely source of the X-ray emission detected at these coordinates.
Psi2 Aquarii, Latinized from ψ2 Aquarii, is the Bayer designation for a star in the equatorial constellation of Aquarius. It is visible to the naked eye with an apparent visual magnitude of 4.4. Based upon parallax measurements made during the Hipparcos mission, the distance to this star is roughly . This is a B-type main sequence star with a stellar classification of B5 Vn. The 'n' suffix indicates that the absorption lines in the spectrum are being broadened by Doppler shift from the star's rapid rotation rate.
The brighter component, ζ Aquarii A (also called ζ2 Aquarii), is a yellow-white-hued F-type main sequence star with an apparent magnitude of +4.42. Its companion, ζ Aquarii B (also called ζ1 Aquarii), is a yellow-white-hued F-type subgiant with an apparent magnitude of +4.51. The fact that their brightness is so similar makes the pair easy to measure and resolve. Zeta Aquarii A is known to be an astrometric binary system, as it undergoes regular perturbations from its orbit.
The stellar classification of this object matches a massive, early B-type star with a luminosity class of IV or V, corresponding to a subgiant or main sequence star, respectively. It is 20 million years old with nearly ten times the mass of the Sun and is spinning with a projected rotational velocity of 41 km/s. The strength of the stellar magnetic field has been measured at . The star is radiating 3,632 times the Sun's luminosity from its photosphere at an effective temperature of 22,420 K.
3 Corvi is a single star in the southern constellation of Corvus, located 192 light years away from the Sun. It is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of 5.45. This object is moving further from the Earth with a heliocentric radial velocity of +14 km/s. This is an A-type main-sequence star with a stellar classification of A1 V. It has 2.14 times the mass of the Sun and 1.87 times the Sun's radius.
HN Pegasi is the variable star designation for a young, Sun-like star in the northern constellation of Pegasus. It has an apparent visual magnitude of 5.9, which, according to the Bortle scale, indicates that it is visible to the naked eye from suburban skies. Parallax measurements made by the Hipparcos spacecraft put the star at a distance of around 58 light years. This is a G-type main sequence star with a stellar classification of and an estimated age of just 237 million years.
The white dwarf primary has 63% of the Sun's mass but a radius of only about 1% of the Sun. As of 2009, it has the shortest known spin period of any white dwarf, completing a full revolution every 33.08 seconds. This spin is decreasing at a rate of 1.78 ns per year, which is unusually high. The secondary star has a stellar classification of K4-5 V, making it a main sequence star that is generating energy at its core through the thermonuclear fusion of hydrogen.
This is a suspected binary star system, with a companion star at an angular separation of along a position angle of from the primary, as of 2008. This corresponds to a projected separation of . The brighter component is an A-type main sequence star with a stellar classification of A3 V. The system is a source of X-ray emission with a luminosity of , which is most likely originating from the cooler companion since A-type main sequence stars are not expected to be magnetically active.
HD 138573 is G-type main-sequence star in the constellation Serpens, class G5IV-V, roughly 100.8 light years from Earth (30.912 parsecs). Though a G type star like the Sun, a 2005 study found that it is not a solar twin as HD 138573 has a much lower mass, lower metallicity, and is much older age than the Sun at 5.6 billion years old. HD 138573 is otherwise close to the Sun's characteristics and could be classed as a Solar analog. Mahdi et al.
HD 189245 is the Henry Draper catalogue designation for a solitary star in the southern constellation of Sagittarius. It has an apparent visual magnitude of 5.66, which means it is faintly visible to the naked eye. Parallax measurements from the Hipparcos satellite indicate a distance of around 69 light years from the Sun. The stellar classification of this star is , indicating that it is an F-type main sequence star with a spectrum that shows deficiencies in iron (Fe) and methylidyne (CH) in its outer atmosphere.
Beta, Delta and Zeta constitute the Tien Kang ("heavenly rope") in China.Richard Hinckley Allen: Star Names — Their Lore and Meaning: Piscis Australis, the Southern Fish Beta is a white main sequence star of apparent magnitude 4.29 that is of similar size and luminosity to Fomalhaut but five times as remote, at around 143 ± 1 light- years distant from Earth. Delta Piscis Austrini is a double star with components of magnitude 4.2 and 9.2. The brighter is a yellow giant of spectral type G8 III.
Astronomers made more sense of its pulsations when it became clear that it is also a binary star system. The main star is a white main sequence star of spectral type A4V that is around 1.85 ± 0.05 times as massive as the Sun. Its companion is most likely a red dwarf of spectral type M3V, around 0.3 times as massive as the Sun. The two are very close—possibly only 3 times the diameter of the Sun between them—and orbit each other every 1.15 days.
HD 215456 is a star in the southern constellation Grus. It is a dim, yellow- hued star that lies just below the normal limit for visibility to the naked eye with an apparent visual magnitude of 6.63. The distance to this star is 129 light years based on parallax, and it has an absolute magnitude of 3.73. It is drifting closer with a radial velocity of −18.9 km/s. This object is a solar-type main-sequence star with a stellar classification of G0.5V.
Ghulam Murtaza (born 3 January 1939), , is a Pakistani theoretical physicist with a specialization in the physics of ionized plasmas, and is an Emeritus Professor of physics at the Government College University in Lahore. Murtaza's work is recognizable in plasma physics and controlled nuclear fusion processes to provide a better understanding of energy propagated by the main-sequence star, the Sun. From 2000 till 2020, Murtaza served on the science faculty of the Government College University where he directed the Abdus Salam Chair in Physics.
The primary star, HD 109749 A, is a G-type subgiant with a spectral type of G3IV, indicating it is an evolved star with a luminosity higher than that of a main sequence star. It has a mass of and a radius of . The star is shining with a luminosity of and has an effective temperature of 5,860 K. Evolutionary models estimate an age of 4.1 billion years. HD 109749 A is chromospherically inactive and has a high metallicity, with an iron abundance 178% of Sun's.
The primary star has a spectral classification F3IV-V, matching the evidence for a star that is evolving off the main sequence and is expanding its radius. The secondary is thought to be a main sequence star with spectral type G0. It is not visible in the spectrum of DS Andromedae, but the temperature and spectral type can be estimated from the difference in brightness of the two components, determined from the eclipses. The two components are modelled to have apparent magnitudes of 10.62 and 12.47 respectively.
Altair in comparison with the Sun Along with β Aquilae and γ Aquilae, Altair forms the well-known line of stars sometimes referred to as the Family of Aquila or Shaft of Aquila.p. 190, Schaaf 2008. Altair is a type-A main sequence star with about 1.8 times the mass of the Sun and 11 times its luminosity. Altair rotates rapidly, with a rotational period of about 9 hours; for comparison, the equator of the Sun makes a complete rotation in a little more than 25 days.
Kepler-69 (KOI-172, 2MASS J19330262+4452080, KIC 8692861) is a G-type main- sequence star similar to the Sun in the constellation Cygnus, located about from Earth. On April 18, 2013 it was announced that the star has two planets. Although initial estimates indicated that the terrestrial planet Kepler-69c might be within the star's habitable zone, further analysis showed that the planet very likely is interior to the habitable zone and is far more analogous to Venus than to Earth and thus completely inhospitable.
This object is an A-type main-sequence star with a stellar classification of A2Vnn. The 'nn' suffix indicates "nebulous" (broad) absorption lines in the spectrum due to rapid rotation. It is spinning with a projected rotational velocity of 250 km/s, which is giving the star an equatorial bulge that is estimated to be 15% larger than the polar radius. The object is an estimated 71 million years old with 1.8 times the mass of the Sun and about 2.7 times the Sun's radius.
The system is around 1,434 light-years away from Earth. Originally named and discovered to be variable in 1949, RZ Gruis was discovered to be a cataclysmic variable after its spectrum was investigated in 1980. Considered initially to be a hot, blue B-type star, it was found to have Balmer spectral lines of the hydrogen atom. If it were indeed a B-type main-sequence star (and hence lie at a remote 35,000 light-years' distance), it would lie well out of the galactic plane.
HD 202206 is a binary star system in the southern constellation of Capricornus. With an apparent visual magnitude of +8.1, it is too faint to be visible to the naked eye. It is located at a distance of 150 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +14.7 km/s. The primary component is a G-type main-sequence star with a stellar classification of G6V, indicating it is generating energy through core hydrogen fusion.
Beta Pictoris b (abbreviated as β Pic b) is an exoplanet orbiting the young debris disk A-type main sequence star Beta Pictoris located approximately 63 light-years (19.4 parsecs, or nearly km) away from Earth in the constellation of Pictor. It has a mass around 13 Jupiter masses and a radius around 46% larger than Jupiter's. It orbits at 9 AU from Beta Pictoris (close to the plane of the debris disk orbiting the star) with a low eccentricity and a period of 20–21 years.
Fomalhaut, K-type main-sequence star TW Piscis Austrini, and M-type, red dwarf star LP 876-10 constitute a triple system, even though the companions are separated by approximately 8 degrees. Fomalhaut was the first stellar system with an extrasolar planet candidate (designated Fomalhaut b, later named Dagon) imaged at visible wavelengths. Analysis of existing and new data suggests Fomalhaut b is not a planet, rather an expanding dust disk resulting from a former collision. The image was published in Science in November 2008.
It ranges in apparent magnitude from 1.59 to 1.64. The spectral types for O and early B stars were defined more rigorously in 1971 and Bellatrix was used as a standard for the B2 III type. The expected brightness of Bellatrix from this spectral type is about one magnitude brighter than calculated from its apparent magnitude and Hipparcos distance. Analysis of the observed characteristics of the star indicate that it should be a B2 main sequence star, not the giant that it appears from its spectral type.
HD 12467 is a single star in the northern circumpolar constellation of Cepheus. It has a white hue and is barely visible to the naked eye with an apparent visual magnitude of 6.05. The distance to this object is 231 light years based on parallax, but it is drifting closer with a heliocentric radial velocity of −9 km/s. This object is an ordinary A-type main-sequence star with a stellar classification of A1.5V, which indicates it is generating energy through core hydrogen fusion.
90 Tauri (90 Tau) is a star in the zodiac constellation of Taurus, located 144 light years away from the Sun. It is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of 4.27. 90 Tauri is a member of the Hyades cluster and is listed as a double star. This is an A-type main-sequence star with a stellar classification of A6 V. It has 2.1 times the mass of the Sun and 2.8 times the Sun's radius.
AD Leonis is an M-type star with a spectral type M3.5eV, indicating it is a main sequence star that displays emission lines in its spectrum. At a trigonometric distance of , it has an apparent visual magnitude of 9.43. It has about 39–42% of the Sun's mass — above the mass at which a star is fully convective — and 39% of the Sun's radius. The projected rotation of this star is only 3 km/s, but it completes a rotation once every 2.24 days.
HD 4203 is a single star in the equatorial constellation of Pisces, near the northern constellation border with Andromeda. It has a yellow hue and is too faint to be viewed with the naked eye, having an apparent visual magnitude of 8.70. The distance to this object is 266 light years based on parallax, but it is drifting closer to the Sun with a radial velocity of −14 km/s. This object is an ordinary G-type main-sequence star with a stellar classification of G5V.
Kepler-16 is an eclipsing binary star system in the constellation of Cygnus that was targeted by the Kepler spacecraft. Both stars are smaller than the Sun; the primary, Kepler-16A, is a K-type main-sequence star and the secondary, Kepler-16B, is an M-type red dwarf. They are separated by 0.22 AU, and complete an orbit around a common center of mass every 41 days. The system is host to one known extrasolar planet in circumbinary orbit: the Saturn-sized Kepler-16b.
It is a member of the Upper Centaurus-Lupus subgroup of the Scorpius–Centaurus Association. This is an ordinary B-type main sequence star with a stellar classification of B4 V. It has an estimated 6.1 times the mass of the Sun and about 3.4 times the Sun's radius. The star is roughly 40 million years and is spinning with a projected rotational velocity of 141 km/s. It is radiating about 800 times the solar luminosity from its photosphere at an effective temperature of 16,780 K.
This object is a B-type main- sequence star with a stellar classification of B5V, a massive star that is currently generating energy through hydrogen fusion at its core. It is around 234 million years old and spinning rapidly with a projected rotational velocity of 260 km/s. The star has 4.6 times the mass of the Sun and about 3.4 times the Sun's radius. It is radiating 950 times the luminosity of the Sun from its photosphere at an effective temperature of 15,301 K.
This bolometric correction is approximately one magnitude for mid B, late K, and early M stars, increasing to three magnitudes (a factor of 15) for O and mid M stars. All supergiants are larger and more luminous than main sequence stars of the same temperature. This means that hot supergiants lie on a relatively narrow band above bright main sequence stars. A B0 main sequence star has an absolute magnitude of about −5, meaning that all B0 supergiants are significantly brighter than absolute magnitude −5\.
In November 2018, the 8th magnitude star, HD 186302 became the second star identified to be a solar sibling, this one being particularly sun like, same spectra G2, virtually the same mass as well, with a twin spectra revealing identical metallicity.Did Astronomers Just Find The Sun’s Sister? Bob P. King, November 24, 2018 The first star identified as a solar sibling in May 2014, HD 162826, within Hercules is an F type main sequence star somewhat more powerful than the Sun, with a mass 15% greater.
This is an anomalous change in the strength of the spectral lines over the course of an orbit, where the lines become weaker as the star is moving away from the observer. It may be caused by a strong stellar wind from the primary scattering the light from secondary when it is receding. This star is smaller than the primary, with about 7 times the mass of the Sun and 3.6 times the Sun's radius. Its stellar classification is B2 V, making this a main-sequence star.
G 99-47's mass is 0.71 ± 0.03 Solar masses; its surface gravity is 108.20 ± 0.05 (1.58 · 108) cm·s−2, or approximately 162 000 of Earth's, corresponding to a radius 7711 km, or 121% of Earth's. Its temperature is 5790 ± 110 K, almost like the Sun's; its cooling age, i. e. age as degenerate star (not including lifetime as main sequence star and as giant star) is 3.97 Gyr. Due almost equal to the Sun's temperature, GJ 1087 should appear almost the same color as the Sun.
This is a white-hued A-type main sequence star with a stellar classification of A1 V. It is a magnetic Ap star, indicating the spectrum displays chemically peculiar features. The star has an estimated 2.50 times the mass of the Sun and about 2.2 times the Sun's radius. It is 155 million years old and is spinning rapidly with a projected rotational velocity of 192.5 km/s. Lambda Capricorni is radiating 45 times the Sun's luminosity from its photosphere at an effective temperature of 10,674 K.
It is moving closer with a heliocentric radial velocity of −64 km/s, and will approach to within in around 240,600 years. The primary component is an F-type main-sequence star with a stellar classification of , showing a mild underabundance of iron in its spectrum. It is about 3.4 billion years old with 1.14 times the mass of the Sun and about 1.3 times the Sun's radius. This star is radiating 3.12 times the Sun's luminosity from its photosphere at an effective temperature of 6,346 K.
The primary, designated component A, is a K-type main sequence star with a stellar classification of K0 V. It is around one billion years old and is spinning with a projected rotational velocity of 4 km/s.The star has 84% of the mass of the Sun and 86% of the Sun's radius. It is radiating 50% of the luminosity of the Sun from its photosphere at an effective temperature of 5,313 K. Component B has an estimated 45% of the mass of the Sun.
Its companion, almost 3 arcminutes away, is a 13th-magnitude star which may or may not be in orbit around Beta. The remaining member of the triangle is Gamma Trianguli Australis with an apparent magnitude of 2.87. It is an A-type main sequence star of spectral class A1 V, which lies away. Located outside the triangle near Beta, Delta Trianguli Australis is the fourth-brightest star at apparent magnitude +3.8. It is a yellow giant of spectral type G2Ib-II and lies away.
Kepler-41 or KOI-196 is a star in the constellation Cygnus. It is a G-type main-sequence star, like the Sun, and it is located about 3,680 light-years (1130 parsecs) away. It is fairly similar to the Sun, with 115% of its mass, a radius of 129% times that of the Sun, and a surface temperature of 5,750 K. Search for stellar companions to Kepler-41 in 2013-2014 has yielded inconclusive results, compatible with Kepler-41 being the single star.
13 Scorpii is a spectroscopic binary, meaning the two stars are too close to be individually resolved, but periodic Doppler shifts in the star's spectrum indicate there must be orbital motion. In this case, light from only one of its stars can be detected and it is a double- lined spectroscopic binary. The two have an orbital period of 5.7805 days and an eccentricity of 0.19. The primary star, at 11 million years old, is a B-type main-sequence star with a spectral type of B2V.
Just over 3.5 degrees from the north celestial pole, Delta is a white main-sequence star of spectral type A1V with an apparent magnitude of 4.35, located 172±1 light-years from Earth. Bearing the proper name of Yildun, it has around 2.8 times the diameter and 47 times the luminosity of the Sun. A triple star system, Epsilon Ursae Minoris shines with a combined average light of magnitude 4.22. A yellow giant of spectral type G5III, the primary is an RS Canum Venaticorum variable star.
70 Cancri is a star in the zodiac constellation of Cancer, located around 580 light years from the Sun. It is a challenge to view with the naked eye even under good seeing conditions, having an apparent visual magnitude of 6.7. The star is moving closer to the Earth with a heliocentric radial velocity of -21 km/s, and is expected to come to within in around nine million years. It is an A-type main-sequence star with a stellar classification of A1V.
The star has a relatively high proper motion, traversing the celestial sphere at the rate of 0.353 arc seconds per year. It is moving closer to the Sun with a radial velocity of −35.6 km/s. This is an ordinary F-type main-sequence star with a stellar classification of F5 V. It has 1.23 times the mass of the Sun and 1.64 times the Sun's radius. The star is around three billion years old and is spinning with a projected rotational velocity of 8 km/s.
17 Canis Majoris is a single star in the southern constellation of Canis Major, located 610 light years away from the Sun. It is visible to the naked eye as a dim, white-hued star with an apparent visual magnitude of 5.80. The object is moving closer to the Earth with a heliocentric radial velocity of −13 km/s. This is an A-type main-sequence star with a stellar classification of A2 V, and is near the end of its main sequence lifetime.
83 Cancri has a relatively high proper motion, traversing the celestial sphere at an angular rate of per annum. The pair have an orbital period of around 32 days and an eccentricity of about 0.6. The visible member of this system, designated component A, is an F-type main- sequence star with a stellar classification of F4V. Its atmosphere is enhanced with s-process elements, particularly strontium and yttrium, which is attributed to mass transfer from the companion while the latter was on the asymptotic giant branch.
Psi Persei (Psi Per, ψ Persei, ψ Per) is a Be star in the northern constellation of Perseus. It has an apparent visual magnitude of 4.31, so it is visible to the naked eye at night under suitably dark skies. Based on parallax measurements, it is located at a distance of roughly from the Earth. This star has a stellar classification of B5Ve, which indicates it is a B-type main sequence star that is generating energy at its core through the nuclear fusion of hydrogen.
HD 187085 is a yellow–hued star in the southern constellation of Sagittarius. It is too faint to be visible to the naked eye, having an apparent visual magnitude of +7.225. The star is located at a distance of approximately 1,010 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +18 km/s. This is an ordinary G-type main-sequence star with a stellar classification of G0V, which means it is generating energy through core hydrogen fusion.
It has a peculiar velocity of relative to its neighbors, and is probably (86% chance) a runaway star. This is a B-type main sequence star with a stellar classification of B9 V. It has an estimated 2.38 times the mass of the Sun and radiates 10.6 times the Sun's luminosity from its outer atmosphere at an effective temperature of 9,725 K. Xi2 Lupi is about 381 million years old and is spinning relatively rapidly with a projected rotational velocity of 184 km/s.
Those models that fail to satisfy these constraints are therefore subject to rejection or correction by the scientific community. Lithium is readily consumed by fusion with protons at temperatures above , such as is found in the cores of stars. Thus, if the convection zone of a main sequence star carries lithium to the core region, the abundance of lithium in the star can decrease. Likewise, lithium can be produced in interstellar matter by spallation collisions with cosmic rays, or by the evolution of stars of moderate mass.
The primary component is a B-type main sequence star with a stellar classification of B8 Vn. The suffix 'n' indicates 'nebulous' absorption lines in the star's spectrum caused by the Doppler effect of rapid rotation. It has a projected rotational velocity of 175 km/s. This is creating an equatorial bulge that is 12% larger than the star's polar radius. It is a candidate member of the AB Doradus moving group and has an orbiting companion at an angular separation of 0.3 arcseconds.
13 Trianguli is the Flamsteed designation for a star in the northern constellation of Triangulum. It has an apparent visual magnitude of 5.86, so according to the Bortle scale it is faintly visible from dark suburban skies. Measurements made with the Hipparcos spacecraft show an annual parallax shift of 0.03184″, which is equivalent to a distance of around from the Sun. A stellar classification of G0 V indicates this is a main sequence star that is generating energy by fusing hydrogen into helium at its core.
These stars are short period (six hours at most) pulsating stars that have been used as standard candles and as subjects to study astroseismology. Delta Boötis is a wide double star with a primary of magnitude 3.5 and a secondary of magnitude 7.8. The primary is a yellow giant that has cooled and expanded to 10.4 times the diameter of the Sun. Of spectral class G8IV, it is around 121 light-years away, while the secondary is a yellow main sequence star of spectral type G0V.
It consists of a magnitude 6.76 primary component with a dimmer magnitude 8.07 secondary. As of 2015 the pair had an angular separation of along a position angle of 175°. The two stars orbit each other with a period of 450 years with an eccentricity of 0.80. The primary is an A-type main-sequence star with a stellar classification of A9 V. At the estimated age of 863 million years, it is spinning rapidly with a projected rotational velocity of 149 km/s.
HD 181720 b is an extrasolar planet which orbits the G-type main sequence star HD 181720, located approximately 190 light years away in the constellation Sagittarius. This planet has at least three-eighths the mass of Jupiter and takes over two and five-eighths years to orbit the star at a semimajor axis of 1.78 AU with an eccentricity of 0.26. This planet was detected by HARPS on October 19, 2009, together with 29 other planets. The planet HD 181720 b is named Toge.
This object is an ordinary G-type main-sequence star with a stellar classification of G5V, with the luminosity class of 'V' indicating it is generating energy through hydrogen fusion at its core. It is around six billion years old with a leisurely rotation rate, having a projected rotational velocity of 2 km/s. The level of magnetic activity in the chromosphere is considered very low and it has a near solar metallicity. Being a solar twin, has nearly the same mass and radius as the Sun.
The system is a complex one as the faint star GJ 3021B orbits at a distance of 68 AU; it is a red dwarf of spectral type M4V. HD 20003 is a star of magnitude 8.37. It is a yellow main sequence star of spectral type G8V a little cooler and smaller than our Sun around 143 light- years away. It has two planets that are around 12 and 13.5 times as massive as the Earth with periods of just under 12 and 34 days respectively.
Houk (1978) listed a stellar classification of F2/3 V for Nu Caeli, which would indicate this is an F-type main-sequence star. In contrast, Malaroda (1975) assigned in to class F1 III-IV, which would suggest it is a more evolved F-type subgiant/giant transitional hydrid. It is an estimated 880 million years old with 1.34 times the mass of the Sun. The star is radiating eight times the Sun's luminosity from its photosphere at an effective temperature of 6,870 K.
The star is moving further away with a heliocentric radial velocity of +27 km/s. This is a B-type main-sequence star with a stellar classification of B8 Ve. The 'e' suffix indicates the presence of emission lines in the spectrum from ejected circumstellar material that is being heated by the host star. At the age of 126 million years, it has completed 96% of its lifespan on the main sequence. Levenhagen and Leister (2006) class it as a B9 IVe star, which would suggest it has already evolved into a subgiant star.
Gamma Leporis is a member of the Ursa Major Moving Group. This is an F-type main-sequence star with a stellar classification of F6 V. It is larger than the Sun with 1.2 times the radius of the Sun and 1.3 times the Sun's mass. The star is around 1.3 billion years old and is spinning with a rotation period of about six days. Based upon its stellar characteristics and distance from Earth, Gamma Leporis was considered a high- priority target for NASA's Terrestrial Planet Finder mission.
After a main-sequence star has exhausted its core hydrogen, it begins to fuse hydrogen in a thick shell around a core consisting largely of helium. The mass of the helium core is below the Schönberg–Chandrasekhar limit and is in thermal equilibrium, and the star is a subgiant. Any additional energy production from the shell fusion is consumed in inflating the envelope and the star cools but does not increase in luminosity. Shell hydrogen fusion continues in stars of roughly solar mass until the helium core increases in mass sufficiently that it becomes degenerate.
In the wavelength range 3200–8800 Â, the energy emission of this star is very similar to the Sun, and thus it is considered a solar analog. The luminosity class 'V' means this is a main sequence star that is generating energy through the thermonuclear fusion of hydrogen at its core. The effective temperature of the outer envelope of HD 44594 is 5,840 K, which is giving it the characteristic yellow hue of a G-type star. This star has about 108% of the Sun's mass and is about the same radius as the Sun.
The two pairs are separated by over an arcsecond, so the wide visual orbit is poorly known. A preliminary range of orbits has been calculated, with an orbital period of 300 to 430 years, as well as a moderate eccentricity of 0.3 to 0.6. The primary component, HD 98800 A, is a K-type main-sequence star with a varying radial velocity. This indicates the presence of another star orbiting it, but light from that star cannot be detected, so the system is a single-lined spectroscopic binary.

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