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It was like, 'Junk, junk, variable star — ooh, planet!

This image from the Corona Australis constellation shows a variable star in the upper left.

Known as a variable star system, the light from R Aquarii fluctuates, as seen from Earth.

It's a variable star, which means it regularly dims and brightens, in cycles that can last about 420 days.

Variable star KIC 8462852, also known as Tabby's Star and Boyajian's Star, is located more than 1,000 light years from Earth.

She is heading up a team of researchers from the American Association of Variable Star Observers (AAVSO) who are watching the star's every move.

There's a lot of history with such star systems; the first relevant observation of a variable star that contemporary astronomers can refer back to was in the 17th century.

Every 1.97 minutes, it dramatically bursts out with a pulse of light four times brighter than its normal flux, leading astronomers to originally classify it as a lone variable star.

Arcavi soon convinced himself that the light source, designated iPTF14hls, must not be a supernova after all but rather a nearby pulsating (or "variable") star superimposed by coincidence on the distant galaxy.

The star could be in one of its dimming cycles—Betelgeuse is classified as a variable star, a type known for growing brighter and darker—or it could be about to explode.

This insight was used by the astronomer Edwin Hubble in 1923 to measure a Cepheid variable star in the Andromeda nebula, thereby proving the existence of a galaxy outside of our own for the first time.

AR Scorpii, previously identified as a single, variable star, is actually two, a compact white dwarf the size of the Earth but 200,000 times more massive, and a cool red dwarf a third the size of the Sun.

Z Apodis (Z Aps) is a variable star in the constellation of Apus. It has an apparent visual magnitude which varies between 10.7 and 12.7, over a period of 39.37 days. Although described in the General Catalogue of Variable Stars as a cataclysmic variable star, it appears that it is a pulsating variable star, and has been classed as an RV Tauri variable star, type A.

Before its outburst, it had been noted as a variable star of magnitude 12. It gained its name in the 1968 IAU variable star name list.

Mu1 Cancri is a variable star and was given the variable star designation BL Cancri. It is a slow irregular variable with periods of 22.6, 37.8, and 203.7 days.

U Orionis (abbreviated U Ori) is a Mira-type variable star in the constellation Orion. It is a classical long period variable star that has been well observed for over 120 years.

DL Crucis is a variable star in the constellation Crux.

A0620-00 also bears the variable star designation V616 Monocerotis.

It was given the variable star designation AG Draconis in 1964.

It was given the variable star designation TZ Arietis in 1970.

HD 220035 is variable star in the equatorial constellation of Aquarius.

NO Aurigae is a pulsating variable star in the constellation Auriga.

In addition to comets, he was also a variable star observer.

13 Boötis, also known by its variable star designation CF Boötis, is a variable star in the constellation Boötes. It is approximately 550 light-years from Earth, based on its parallax. 13 Boötis is a M-type red giant with a mean apparent magnitude of +5.26. It is classified as an irregular variable star and its brightness varies from magnitude +5.29 to +5.38.

TX Camelopardalis (abbreviated TX Cam) is a Mira-type variable star in the constellation Camelopardalis. It is a classical long period variable star with pulsational period of 558.7 days. Water masers have been observed around the star.

HD 219659 is suspected variable star in the equatorial constellation of Aquarius.

HD 183144 is suspected variable star in the equatorial constellation of Aquila.

There is one candidate B-type variable star, which is 9th magnitude.

Heinlein's original title for Variable Star was The Stars are a Clock.

TW Pictoris is a cataclysmic variable star system located in the constellation Pictor.

HD 126141 is a suspected variable star in the northern constellation of Boötes.

HD 135530 is a suspected variable star in the northern constellation of Boötes.

HD 126271 is a suspected variable star in the northern constellation of Boötes.

HD 125658 is a candidate variable star in the northern constellation of Boötes.

W Aquilae (W Aql) is a variable star in the constellation of Aquila.

V602 Car is a semiregular variable star with a maximum brightness range of magnitude 7.6 - 9.1 and a period of 635 or 672 days. Despite the large amplitude of variation, it was only named as a variable star in 2006.

28 Andromedae (abbreviated 28 And) is a Delta Scuti variable star in the constellation Andromeda. 28 Andromedae is the Flamsteed designation. It also bears the variable star name GN Andromedae. Its apparent magnitude is 5.214, varying by less than 0.1 magnitudes.

HD 182475 is a Delta Scuti variable star in the equatorial constellation of Aquila.

It is a suspected variable star that ranges in magnitude from 4.33 to 4.37.

It forms part of a double star along with a fainter optical companion designated Gamma¹ Sagittarii located about 50 arcminutes north of this star. The latter is a magnitude 4.7 Cepheid variable star that also has the variable star designation W Sagittarii.

1 Geminorum is listed as a suspected variable star with an amplitude of 0.05 magnitudes.

HD 126009 or CI Boötis is a variable star in the northern constellation of Boötes.

R Reticuli (R Ret) is a Mira variable star in the constellation Reticulum. It varies between magnitudes 6.35 and 14.2 over a period of 281 days. Although this star was also assigned the variable star designation S Reticuli, this designation is no longer in use.

V915 Scorpii (HR 6392, HD 155603) is an orange hypergiant variable star in the constellation Scorpius.

It was later referred to as Variabilis Coronae, "Variable (star) of Corona (Borealis)". It has also been called a "reverse nova" because of its habit of fading from sight. The variable star designation R Coronae Borealis was introduced, as "Coronae R" by Friedrich Wilhelm Argelander in 1850.

Bunch, Bryan H. and Hellemans, Alexander (2004) The History of Science and Technology: A Browser's Guide to the Great Discoveries, Inventions, and the People Who Made Them, from the Dawn of Time to Today. Boston: Houghton Mifflin. In 1882 he started his appeals for international variable star observations. This was met with opposition, but eventually such a cooperation was realized in the Variable Star Section of the British Astronomical Association and the American Association of Variable Star Observers (AAVSO).

The variability was discovered in 1959, and it has been assigned the variable star designation ES Vulpeculae.

For that, it has been given the variable star designation QS Vulpeculae; 22 Vulpeculae is the Flamsteed designation.

It was assigned the variable star designation QV Andromedae in the 73rd namelist of variable stars in 1997.

Component B has been observed to fluctuate in brightness and is catalogued as suspected variable star NSV 2008.

Since its founding in 1911, the American Association of Variable Star Observers (AAVSO) has coordinated, collected, evaluated, analyzed, published, and archived variable star observations made largely by amateur astronomers and makes the records available to professional astronomers, researchers, and educators. These records establish light curves depicting the variation in brightness of a star over time. Since professional astronomers do not have the time or the resources to monitor every variable star, astronomy is one of the few sciences where amateurs can make genuine contributions to scientific research. During 2011, the 100th year of the AAVSO's existence, the 20-millionth variable star observation was received into the database. The AAVSO International Database currently stores over 35 million observations.

BU Crucis is a variable star with a brightness range of about 0.1 magnitudes. It is listed as a probable eclipsing binary in the General Catalogue of Variable Stars, but the International Variable Star Index classifies it as an α Cygni variable with a visual magnitude range of 6.82 - 7.01.

R Apodis (R Aps) is a star in the constellation Apus. R Apodis is an orange K-type giant with an apparent magnitude of +5.34. It is approximately 386 light years from Earth. It was earlier suspected to be a variable star and given the variable star designation R Apodis.

LP Aquarii is a pulsating variable star in the constellation of Aquarius that varies between magnitudes 6.30 and 6.64.

Janet Akyuz Mattei was a Turkish-American astronomer who directed the American Association of Variable Star Observers for years.

It is classified as a Gamma Cassiopeiae type variable star and its brightness varies from magnitude +4.68 to +4.89.

A Gamma Cassiopeiae variable (γ Cassiopeiae variable) is a type of variable star, named for its prototype γ Cassiopeiae.

Sigma Canis Majoris was noted as a likely variable star in a list of bright southern stars studied at the Cape Observatory. The variability was confirmed in 1963, and it was formally catalogued as a variable star. It is classified as an irregular variable star and its brightness varies from magnitude +3.43 to +3.51. The magnetic field of this star has a strength below 1 G. It is suspected of being a member of the Collinder 121 stellar association of co-moving stars, but this is disputed.

The variation in VY CMa's brightness was first described in 1931 when it was listed (in German) as a long-period variable with a photographic magnitude range of 9.5 to 11.5. It was given the variable star designation VY Canis Majoris in 1939, the 43rd variable star of the constellation Canis Major.

VY Canis Majoris is a variable star that varies from an apparent visual magnitude of 9.6 at minimum brightness to a magnitude of 6.5 at maximum brightness with an estimated pulsational period of 956 days. In the General Catalogue of Variable Stars (GCVS) it is classed a semiregular variable of sub-type SRc, indicating a cool supergiant, although it is classed as a type LC slow irregular variable star in the American Association of Variable Star Observers (AAVSO) Variable Star Index. Other periods of 1,600 and 2,200 days have been derived. VY CMa is sometimes considered as the prototype for a class of heavily mass-losing OH/IR supergiants, distinct from the more common asymptotic giant branch OH/IR stars.

"The Free Lunch". Publisher's Weekly review.. In an afterword to Variable Star he recounts the story of how reading Rocket Ship Galileo and soon after Heinlein's other Heinlein juvenile novels helped set the direction for his life, and how he came to write the novel."VARIABLE STAR ". review in Audiophile magazine, February-March 2008.

The tertiary is not visible in telescopes. AA Ceti is an eclipsing variable star; the tertiary star passes in front of the primary and causes the system's apparent magnitude to decrease by 0.5 magnitudes. UV Ceti is an unusual binary variable star. 8.7 light-years from Earth, the system consists of two red dwarfs.

Although designated as a variable star, observations with the Hipparcos satellite showed a variation of no more than 0.02 in magnitude. In designating this as a suspected variable star, it is possible that Kappa Ophiuchi was mistaken for Chi Ophiuchi, which is a variable star. Kappa Ophiuchi belongs to an evolutionary branch known as the red clump, making it a clump giant. The surface abundance of elements other than hydrogen and helium, what astronomers term the star's metallicity, is similar to the abundances of those elements in the Sun.

The primary star, also known as Wolf 1055, is a type M2.5 red dwarf with about half the size and mass as the Sun and considerably cooler at 3240 K. This star was first observed to be a high proper motion star by the German astronomer Max Wolf with his pioneering use of astrophotography. He added this star to his extensive catalog of such stars in 1919. It is a variable star with the variable star catalog name V1428 Aquilae. It is a BY Draconis type variable star subject to flare events.

A U Geminorum-type variable star or dwarf nova is a type of cataclysmic variable star consisting of a close binary star system in which one of the components is a white dwarf that accretes matter from a cool main sequence or subgiant companion. V392 Persei was discovered in 1970 and received its variable star designation a year later. It is normally visual magnitude 17.4 and experiences outbursts of 2-3 magnitudes. Its spectrum in the quiescent state has been studied and only the cool star is detected.

IK Tauri or NML Tauri is a Mira variable star located about from the Sun in the zodiac constellation of Taurus.

Romano's Star (GR 290) is a luminous blue variable star located in the Messier 33 galaxy in the constellation of Triangulum.

The cluster also contains around 1300 core helium burning horizontal branch (HB) stars, including at least one RR Lyrae variable star.

X Crucis is a classical Cepheid variable star in the southern constellation of Crux. X Crucis is a pulsating variable star with am extremely regular amplitude and period. Its apparent magnitude varies from 8.1 to 8.7 every 6.22 days. This type of variable is known as a Cepheid after δ Cephei, the first example to be discovered.

X Sagittarii is a bright giant Cepheid variable star in the constellation Sagittarius. This variable star changes in apparent magnitude from 4.90 to 4.20 magnitude with a period of 7.01 days. Its change in brightness is accompanied by a change in spectral classification, from G2 to F5. It is approximately 990 light years away based on parallax.

HR 6819 is the Bright Star Catalogue designation for this star. It also has the Henry Draper Catalogue designation HD 167128 and the Hipparcos designation HIP 89605. Since its brightness varies, it has been given the variable star designation QV Telescopii, indicating that it is the 330th confirmed variable star (excluding stars with Bayer designations) in the constellation Telescopium.

63 Andromedae (abbreviated 63 And) is an Alpha2 Canum Venaticorum (α2 CVn) variable star in the constellation Andromeda. Its variable star designation is PZ Andromedae. With an apparent magnitude of about 5.6, it is bright enough to be seen by naked eye. Based upon an annual parallax shift of , it is located 413 light years away.

53 Cancri is a variable star in the zodiac constellation Cancer, located around 960 light years from the Sun. It has the variable star designation BO Cancri; 53 Cancri is the Flamsteed designation. This object is a challenge to view with the naked eye, having an apparent visual magnitude around 6. It is around 960 light years away.

Kappa Pavonis (κ Pav) is a variable star in the constellation Pavo. It is the brightest W Virginis variable in the sky.

Denebola is a suspected Delta Scuti type variable star, meaning its luminosity varies very slightly over a period of a few hours.

The second Eta is now designated as HD 150550. It is a variable star of average magnitude 6.53 and spectral type A1III.

ST Camelopardalis is a doubly periodic semiregular variable star and carbon star in the constellation of Camelopardalis. It has a radius of .

The Astronomical League awarded Edward Halbach with the Astronomical League Award in 1972. Halbach was the first living recipient of the Leslie C. Peltier Award in 1981 for his variable star and lunar occultation observations and contributions to artificial satellite programs. The American Association of Variable Star Observers honoured him with the Merit Award in 1988, for his record of more than 50,000 observations in the AAVSO International Database and for 54-year service in the society. He also won the Amateur Achievement Award of the Astronomical Society of the Pacific for his variable star and occultation observations in 1997.

SS Virginis is a Mira variable star that appears with a strong red hue. It varies in magnitude from a minimum of 9.5 to a maximum of 7.4 over a period of 361 days. It is also considered to be a semiregular variable star, as its minimum and maximum magnitude are themselves variable over a period of decades. Its spectral class is C63e.

Edward A. Halbach (April 5, 1909 – March 20, 2011) was an American amateur astronomer and prolific variable star observer. He developed his interest in astronomy in 1933. One year later he became a member of the American Association of Variable Star Observers (AAVSO). He was also one of the first members of the Milwaukee Astronomical Society and directed its observatory for 35 years.

HD 183143 was listed as being variable in 1976, with a very small amplitude. During the Hipparcos mission, its brightness was observed to vary between magnitude 6.71 and 6.95. ASAS-3 photometry shows a period of 40.44 days. HD 183143 was formally announced as a variable star, probably of the α Cygni type, in 1979 and given the variable star designation HT Sagittae.

U Andromedae is a variable star in the constellation of Andromeda, at a distance of approximately . It is a star of spectral type M6e and it is classified as a Mira variable. U Andromedae is the variable star designation of this star. Its brightness varies by several magnitudes with a mean period of , although the exact length of each cycle is somewhat variable.

U Arietis is another Mira variable star that ranges in magnitude from a minimum of 15.2 to a maximum of 7.2 with a period of 371.1 days. T Arietis is a semiregular variable star that ranges in magnitude from a minimum of 11.3 to a maximum of 7.5 with a period of 317 days. It is 1,630 light-years away.

HD 123657, or BY Boötis, is a variable star of magnitude 4.98-5.33V. This makes it a dim naked eye star. The star is located near the end of the handle of the Big Dipper, but just within the boundaries of the constellation Boötes. It is a slow irregular red giant variable star with a range of less than half a magnitude.

IX Car is a semiregular variable star with a maximum brightness range of magnitude 7.2 - 8.5 and a period of 408 or 4,400 days.

HD 118508 is a variable star in the northern constellation of Boötes. It varies marginally in luminosity with an amplitude of 0.04 in magnitude.

V473 Lyrae is a variable star in the constellation Lyra. It is an unusual Classical Cepheid variable with a visual range of 5.99 to 6.35.

Another of his discoveries was the variability of Gamma Doradus, which was later shown to be the prototype of a new class of variable star.

The azimuthal equatorial velocity may be . It is a suspected Gamma Cassiopeiae type (GCAS) variable star, with its apparent magnitude varying from 2.62m to 2.66m.

HD 33463 is a suspected variable star in the northern constellation of Auriga. This is a red giant star with a stellar classification of M2III.

It is classified as a luminous blue variable or S Doradus variable with the variable star designation V4029 Sagittarii, although no outbursts have been observed.

It is a possible semiregular variable star with a range of about a tenth of a magnitude. A period of 29 days has been derived.

This is giving the star an oblate spheroid shape with an equatorial bulge that is 24% larger than the polar radius. It is a Delta Scuti variable with a small amplitude and period of 2.5 hours. Gamma Cassiopeiae is the prototype Gamma Cassiopeiae variable star, a type of variable star that has a variable disc of material flung off by the high rotation rate of the star.

The extent of such a zone is not fixed and is highly specific for each planetary system. Gliese 581 is a very old star. Its slow rotation makes it very inactive, making it better suited than most red dwarfs for having habitable planets. Gliese 581 is classified as a variable star of the BY Draconis type, and has been given the variable star designation HO Librae.

The stellar classification of this star has been rated from M1.5V to M4.0V by various sources. Gliese 1 is estimated to have 45–48% of the Sun's mass and 46–48% of the Sun's radius. This star is suspected of being a BY Draconis-type variable star with the provisional variable star designation NSV 15017. It is also suspected of being a flare star.

As a boy, Houston learned to build microscopes and telescopes and developed an interest in amateur astronomy. He soon observed all 103 nebulae and star clusters in the Messier catalog. While at the University of Wisconsin he began observing variable stars and in 1931 he joined the American Association of Variable Star Observers (AAVSO). Eventually, he contributed more than 12,000 variable star observations to AAVSO.

TV Geminorum is classified as a semi-regular variable star, meaning that its brightness changes are not predictable, but do show some periodicity. The General Catalogue of Variable Stars does not list a period, but the International Variable Star Index gives an uncertain period of 229 days. A detailed study of TV Gem between 1997 and 2014 detects periods of 411 days and 3,137 days.

37 Comae Berenices is a variable star system located around 690 light years away from the Sun in the northern constellation of Coma Berenices. It has the variable star designation LU Comae Berenices. 37 Comae Berenices was a later Flamsteed designation of 13 Canum Venaticorum. This object is visible to the naked eye as a faint, yellow-hued star with a baseline apparent visual magnitude of 4.88.

In the Spring of 1927 Professor Ralph Curtiss loaned Ford two books: Splendour of the Heavens and The Friendly Stars. In the back of the latter book's original edition there was an invitation by William Tyler Olcott of the AAVSO to contribute to the advancement of astronomy by observing variable stars. Ford took Olcott and the AAVSO up on that invitation and on September 23, 1927, he reported his first variable star estimate - 184205 R Scuti at 5.3 magnitude. Ford made over 60,000 variable star observations and became the youngest member of the American Association of Variable Star Observers at the age of fifteen.

Mattei, Janet: Carolyn J. Hurless, 1934 - 1987: AAVSO's enthusiastic ambassador. Journal of the American Association of Variable Star Observers, Vol. 16, No. 1, p. 35 - 36.

BU Crucis (HD 111934) is a variable star in the open cluster NGC 4755, which is also known as the Kappa Crucis Cluster or Jewel Box Cluster.

R Canum Venaticorum is a Mira variable star in the constellation Canes Venatici. It ranges between magnitudes 6.5 and 12.9 over a period of approximately 329 days.

7.9 and the hottest star is of spectral type B9. One member, HD 89856 (mag. 9.04, spectral type B9), is a variable star with period 4.556 days.

45 Herculis is a solitary variable star in the northern constellation Hercules. It has the Bayer designation l Herculis and the variable star designation V776 Herculis. The Flamsteed designation for this star comes from the publication Historia Coelestis Britannica by John Flamsteed. It is the 45th star in Flamsteed list of stars in the constellation Hercules, and is visible to the naked eye with a baseline apparent visual magnitude of 5.22.

Gliese 908 is a red dwarf star, located in constellation Pisces at 19.3 light- years from Earth. It is a BY Draconis variable star with a variable star designation of BR Piscium. Its apparent magnitude varies between magnitude 8.93 and magnitude 9.03 as a result of starspots and varying chromospheric activity. The variability of Gliese 908 was confirmed in 1994, although no period could be detected in its brightness changes.

26 Arietis is a variable star in the northern constellation of Aries. 26 Arietis is the Flamsteed designation; it also bears the variable star designation UU Arietis. The apparent visual magnitude of this star is 6.14, which, according to the Bortle Dark-Sky Scale, is within the naked eye visibility limit in dark rural skies. The annual parallax shift of is equivalent to a distance of approximately from Earth.

21 Aquilae is a solitary variable star in the equatorial constellation of Aquila. It has the variable star designation V1288 Aql; 21 Aquilae is its Flamsteed designation. This object is visible to the naked eye as a dim, blue- white hued star with a baseline apparent visual magnitude of 5.14. The star is located at a distance of around from Earth, give or take a 30 light-year margin of error.

15 Arietis (abbreviated 15 Ari) is a single variable star in the northern constellation of Aries. 15 Arietis is the Flamsteed designation; it also bears the variable star designation AV Arietis. It has an apparent visual magnitude of 5.74, which is just bright enough to be visible to the naked eye from dark suburban skies. An annual parallax shift of 5.84 mas corresponds to a physical distance of approximately from Earth.

V419 Cephei (BD+59°2342 or HIP 104719) is an irregular variable star in the constellation of Cepheus with an apparent magnitude that varies between 6.54 and 6.89.

HR 4887 (HD 111904) is a suspected variable star in the open cluster NGC 4755, which is also known as the Kappa Crucis Cluster or Jewel Box Cluster.

In 1947 he was elected the first official president of the Astronomical League. Besides his numerous variable star observations he was interested also in solar astronomy and occultations.

V Antliae (V Ant) is a Mira variable star in the constellation Antlia. It varies in brightness between magnitudes 8.2 and 14.0 with a period of 303 days.

T Cephei is a Mira variable star in the constellation Cepheus. Located approximately distant, it varies between magnitudes 5.2 and 11.3 over a period of around 388 days.

HD 128333 or CH Boötis is an irregular variable star in the northern constellation of Boötes. It is currently on the asymptotic giant branch of the HR diagram.

He is president of the astronomical research institution MoreData! Inc., as well as treasurer of the Society for Astronomical Sciences and the American Association of Variable Star Observers.

W Cygni is a semi-regular variable star in the constellation Cygnus, located 570 light-years from Earth. It lies less than half a degree southeast of ρ Cygni.

V518 Carinae (HR 4196) is a naked-eye variable star in the constellation Carina. It is a member of the bright open cluster IC 2602 near the Carina Nebula.

S Virginis is a Mira-type variable star in the constellation Virgo. Located approximately distant, it varies between magnitudes 6.3 and 13.2 over a period of approximately 375 days.

AE Andromedae (AE And) is a luminous blue variable (LBV), a type of variable star. The star is one of the most luminous variables in M31, the Andromeda Galaxy.

Period-luminosity relations are known for several types of pulsating variable star: type I Cepheids; type II Cepheids; RR Lyrae variables; Mira variables; and other long-period variable stars.

Omicron1 Canis Majoris (ο1 CMa, ο1 Canis Majoris) is a red supergiant star in the constellation Canis Major. It is a variable star in the constellation of Canis Major.

The surface gravity of this relatively compact star is approximately 65 times greater than the gravity at Earth's surface (log g = 4.8 cgs), which is more than twice the surface gravity of our Sun. Lalande 21185 is listed as a BY Draconis type variable star in the General Catalogue of Variable Stars. It is identified by the variable star designation NSV 18593. Several star catalogs, including SIMBAD, also classify it as a flare star.

T Centauri is a variable star located in the far southern constellation Centaurus.SIMBAD, T Centauri (accessed 22 July 2014) It varies between magnitudes 5.56 and 8.44 over 181.4 days. Pulsating between spectral classes K0:e and M4II:e, it has been classed as a semiregular variable, though Sebastian Otero of the American Association of Variable Star Observers has noted its curve more aligned with RV Tauri variable stars and has classified it as one.

FF Aquilae is a classical Cepheid variable star located in the constellation Aquila. It ranges from apparent magnitude 5.18 to 5.51 over a period of 4.470848 days, meaning it is faintly visible to the unaided eye in rural or suburban settings. Originally known as HR 7165, it was noted to be variable by Charles Morse Huffer in August 1927, who observed its Cepheid pattern. It then received the variable star designation FF Aquilae.

IRAS 08544-4431 is classified as an RV Tauri star, a type of pulsating variable star which shows cycles with alternating shallow and deep minima. In addition, IRAS 08544-4431 shows slow variations in amplitude from cycle to cycle over approximately 1,600 days, a defining characteristic of a type b RV Tauri variable. The maximum amplitude is only 0.18 magnitudes. It was given the variable star designation of V390 Velorum in 2006.

36 Aurigae is a single variable star located about 910 light years away from the Sun in the constellation Auriga. It has the variable star designation V444 Aurigae, while 36 Aurigae is the Flamsteed designation. This object is visible to the naked eye as a dim, white-hued star with a baseline apparent visual magnitude of 5.71. It is moving further from the Earth with a heliocentric radial velocity of +16 km/s.

83 Ursae Majoris is a candidate binary star system in the northern circumpolar constellation of Ursa Major. This is a semiregular variable star, like Mira; for that reason it has been given the variable star designation IQ Ursae Majoris. It ranges in brightness from apparent visual magnitude 4.69 to 4.75. Percy and Au (1994) identified it as a small amplitude red variable with an irregular behavior, having a characteristic time scale of 20 days.

AN Ursae Majoris is a binary star system in the northern circumpolar constellation of Ursa Major. It is a variable star, with AN Ursae Majoris being the variable star designation, and ranges in brightness from 14.90 down to 20.2. Even at its peak brightness though, the system is much to faint to be visible to the naked eye. Based on parallax measurements, the system is located roughly 1,050 light years away from the Sun.

With a proper motion of 5.1 arcseconds per year, it is the 24th closest star to Earth overall. Aries has its share of variable stars, including R and U Arietis, Mira-type variable stars, and T Arietis, a semi-regular variable star. R Arietis is a Mira variable star that ranges in magnitude from a minimum of 13.7 to a maximum of 7.4 with a period of 186.8 days. It is 4,080 light-years away.

21 Persei is a single, variable star in the northern constellation of Perseus, located about 331 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 5.10 km/s. The object is moving further from the Earth with a heliocentric radial velocity of +8.5 km/s. It has the variable star designation LT Persei; 21 Persei is the Flamsteed designation.

15 Vulpeculae is a variable star in the northern constellation of Vulpecula, located approximately 236 light years away based on parallax. It has the variable star designation NT Vulpeculae; 15 Vulpeculae is the Flamsteed designation. It is visible to the naked eye as a faint, white-hued star with a typical apparent visual magnitude of 4.66. This object is moving closer to the Earth with a heliocentric radial velocity of −26 km/s.

VB 10 is a variable star and is identified in the General Catalogue of Variable Stars as V1298 Aquilae. It is a UV Ceti-type variable star and is known to be subject to frequent flare events. Its dynamics were studied from the Hubble Space Telescope in the mid-1990s. Although VB 10 has a normal low surface temperature of 2600 K it was found to produce violent flares of up to 100,000 K.

35 Piscium is a triple star system in the northern constellation Pisces, located about 250 light years away from the Sun. Because it is a variable star, it has been given the variable star designation UU Piscium; 35 Piscium is the Flamsteed designation. This system is faintly visible to the naked eye with a combined apparent visual magnitude of 5.88. It is catalogued as a member of the IC 2391 supercluster by Olin J. Eggen.

V725 Sagittarii (V725 Sgr) is a semiregular pulsating variable star in the constellation of Sagittarius. As recently as a century ago, it was a Population II Cepheid; its transformation was documented by Henrietta Swope beginning in 1937, and is one of the most exciting and instructive events in variable-star astronomy.Swope, H. 1937, Harvard College Observatory Annals, 105, 26, 499Demers, S. 1973, Journal of the Royal Astronomical Society of Canada, 67, 19.

Chi Cygni (Latinised from χ Cygni) is a Mira variable star in the constellation Cygnus, and also an S-type star. It is around 500 light years away. χ Cygni is an asymptotic giant branch star, a very cool and luminous red giant nearing the end of its life. It was discovered to be a variable star in 1686 and its apparent visual magnitude varies from as bright as 3.3 to as faint as 14.2.

It is a detached binary with two main sequence components that do not fill their Roche lobes. The orbital plane is oriented near the line of sight from the Earth, making this a Beta Lyrae–type eclipsing binary variable star. It has the variable star designation TU Cameleopardis, while 31 Camelopardalis is the Flamsteed designation. The primary eclipse lowers the visual magnitude to 5.29, while the secondary eclipse lowers it to 5.22.

S Ursae Minoris (S UMi) is a long period variable star in the constellation Ursa Minor, ranging from magnitude 7.5 to fainter than 13.2 over a period of 331 days.

John Goodricke FRS (17 September 1764 – 20 April 1786) was an English amateur astronomer. He is best known for his observations of the variable star Algol (Beta Persei) in 1782.

HD 221148 is suspected variable star in the equatorial constellation of Aquarius. The spectrum of the star shows exceptionally strong levels of CN; one of the highest cyanogen indices measured.

GQ Lupi is a T Tauri variable star approximately 495 light-years away in the constellation of Lupus. The star is young and has about 70% of the Sun's mass.

Nova Persei 2018 is a bright nova in the constellation Perseus discovered on April 29, 2018. It was previously known as a dwarf nova with variable star designation V392 Persei.

He observed more than 49,700 variable stars and became one of the first international members of American Association of Variable Star Observers.The AAVSO and International Cooperation - official website of AAVSO.

Her graduate studies began in 1937 at Harvard University in the department of History of Science. Her dissertation was entitled, The Early History of Variable Star Observing to the 19th Century.

DU Crucis is a red supergiant and slow irregular variable star in the open cluster NGC 4755, which is also known as the Kappa (κ) Crucis Cluster or Jewel Box Cluster.

It was given the variable star designation NS Puppis in 1975. h2 Puppis is another luminous K-type star with almost the same visual magnitude about a degree to the southeast.

HD 29697 (Gliese 174, V834 Tauri) is a variable star of BY Draconis type in the constellation Taurus. It has an apparent magnitude around 8 and is approximately 43 ly away.

Janet Akyüz Mattei (January 2, 1943 - March 22, 2004) was a Turkish-American astronomer who was the director of the American Association of Variable Star Observers (AAVSO) from 1973 to 2004.

Carolyn Hurless (November 24, 1934 – February 13, 1987) was an American astronomer and an American Association of Variable Star Observers merit award winner. She made 78,876 astronomical observations in her lifetime.

78 Virginis is a variable star in the zodiac constellation of Virgo, located 175 light-years from the Sun. It has the variable star designation CW Virginis and the Bayer designation o Virginis; 78 Virginis is the Flamsteed designation. This object is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of 4.92. It is moving closer to the Earth with a heliocentric radial velocity of −10 km/s.

The component k1 Puppis is a binary star system in its own right, while k2 Puppis is a variable star. Each star within the k Puppis optical pair is between 450 and 470 light years from Earth. k Puppis is listed in the General Catalogue of Variable Stars as a suspected variable star, but the range and type are not stated. The International Bulletin of Variable Stars has since published research showing that k2 Puppis is the variable component.

66 Ophiuchi is a solitary variable star in the equatorial constellation of Ophiuchus. It has the variable star designation V2048 Ophiuchi, while 66 Ophiuchi is the Flamsteed designation. This object is visible to the naked eye as a faint, blue-white hued point of light with a baseline apparent visual magnitude of 4.60. It is located approximately 650 light years away from the Sun based on parallax, but is drifting closer with a radial velocity of −13 km/s.

56 Arietis is a single, variable star in the northern zodiac constellation of Aries. It has the variable star designation SX Arietis, while 56 Arietis is the Flamsteed designation. This object is visible to the naked eye as a faint, blue-white hued point of light with a baseline apparent visual magnitude of 5.79. The estimated distance to this star is approximately , based on parallax, and it is drifting further away with a radial velocity of +18 km/s.

70 Aquarii is a variable star located 425 light years away from the Sun in the equatorial constellation of Aquarius. It has the variable star designation FM Aquarii; 70 Aquarii is the Flamsteed designation. It is near the lower limit of visibility to the naked eye, appearing as a dim, yellow-white hued star with a baseline apparent visual magnitude of 6.19. This star is moving closer to the Earth with a heliocentric radial velocity of –5.8 km/s.

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 .

R Cassiopeiae is a variable star in the northern constellation of Cassiopeia. It is located approximately 610 light years distant from the Sun, but is drifting closer with a radial velocity of −23 km/s. This is a pulsating Mira- type variable star with a brightness varies from magnitude +4.4 down to +13.5 with a period of 433.6 days. At its maximum, R Cassiopeiae is visible to the naked eye as a faint, red-hued star.

13 Andromedae, abbreviated 13 And, is a single, blue-white hued variable star in the northern constellation of Andromeda. 13 Andromedae is the Flamsteed designation, while it bears the variable star designation V388 Andromedae. With a typical apparent visual magnitude of around 5.75, it is dimly visible to the naked eye under good seeing conditions. The distance to this star can be directly estimated from its annual parallax shift of , yielding a range of 300 light years.

19 Monocerotis is a single, variable star in the equatorial constellation of Monoceros, located approximately 1,220 light years away from the Sun based on parallax. It has the variable star designation V637 Monocerotis, while 19 Monocerotis is the Flamsteed designation. This object is visible to the naked eye as a faint, blue-white hued star with a baseline apparent visual magnitude of 5.00. It is receding from the Earth with a heliocentric radial velocity of +25 km/s.

R Coronae Borealis-type deep minima in 1992 In 1943, a star designated AN 377.1943 was discovered to be a previously-unknown variable star. It was designated CSV 5066 as a suspected variable, and then FG Sagittae as a confirmed variable star. At the time, its variations were described as being irregular, but it was soon noted that the average brightness was steadily increasing. It brightened by about two magnitudes between 1943 and 1970, and then began to fade.

10 Leonis Minoris is a single, variable star in the northern constellation Leo Minor, located approximately 180 light years away based on parallax. It has the variable star designation SU Leonis Minoris; 10 Leonis Minoris is the Flamsteed designation. This body is visible to the naked eye as a faint, orange-hued star with a baseline apparent visual magnitude of 4.54. It is moving closer to the Earth with a heliocentric radial velocity of −12 km/s.

BL Lacertae or BL Lac is a highly variable, extragalactic active galactic nucleus (AGN or active galaxy). It was first discovered by Cuno Hoffmeister in 1929, but was originally thought to be an irregular variable star in the Milky Way galaxy and so was given a variable star designation. In 1968, the "star" was identified by John Schmitt at the David Dunlap Observatory as a bright, variable radio source. A faint trace of a host galaxy was also found.

HD 179821 is a semiregular variable star with the variable star designation V1427 Aquilae. Between 1899 and 1989, its photographic apparent magnitude varied erratically between about magnitudes 9 and 10, although coverage is not complete and some larger variations may have been missed. It then varied by no more than 0.1 magnitudes until 2009, at a visual magnitude around 8.1. The colour of the star changed noticeably so that the variability at different wavelengths is not consistent.

38 Cancri is a variable star in the zodiac constellation Cancer, located around 607 light years from the Sun. This object has the variable star designation BT Cancri; 38 Cancri is the Flamsteed designation. It is a member of the Praesepe cluster but is a challenge to view with the naked eye, having an apparent visual magnitude of 6.65. The star is moving closer to the Earth with a heliocentric radial velocity of +32 km/s.

6 Geminorum is a variable star in the zodiac constellation of Gemini, located roughly 5,000 light years away from the Sun. It has the variable star designation BU Geminorum; 6 Geminorum is the Flamsteed designation. At its brightest this reddish hued star is barely visible to the naked eye but is readily visible with binoculars, found southwest of M 35, below WY Geminorum. It is moving further from the Earth with a heliocentric radial velocity of +27 km/s.

12 Canis Majoris is a variable star located 750 light years away from the Sun in the southern constellation of Canis Major. It has the variable star designation HK Canis Majoris; 12 Canis Majoris is the Flamsteed designation. This body is just barely visible to the naked eye as a dim, blue-white hued star with a baseline apparent visual magnitude of +6.07. It is moving away from the Earth with a heliocentric radial velocity of +16 km/s.

15 Canis Majoris is a variable star in the southern constellation of Canis Major, located roughly 1,200 light years away from the Sun. It has the variable star designation EY Canis Majoris; 15 Canis Majoris is the Flamsteed designation. The star is visible to the naked eye as a faint, blue-white hued star with a baseline apparent visual magnitude of +4.82. It is moving away from the Earth with a heliocentric radial velocity of 28 km/s.

15 Cancri is an α2 CVn-type variable star in the zodiac constellation of Cancer, located around 980 light years away. It has the variable star designation BM Cancri (BM Cnc); 15 Cancri (15 Cnc) is the Flamsteed designation. This system is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of about 5.6. It is moving away from the Earth with a heliocentric radial velocity of 25 km/s.

The Iris Nebula (also known as NGC 7023 and Caldwell 4) is a bright reflection nebula in the constellation Cepheus. The designation NGC 7023 refers to the open cluster within the larger reflection nebula designated LBN 487. The nebula, which shines at magnitude +6.8, is illuminated by a magnitude +7.4 star designated SAO 19158. It is located near the Mira-type variable star T Cephei, and near the bright magnitude +3.23 variable star Beta Cephei (Alphirk).

36 Lyncis is a solitary variable star located around 570 light years away from the Sun in the northern constellation of Lynx. It has the variable star designation of EI Lyncis, while 36 Lyncis is the Flamsteed designation. This object is visible to the naked eye as a dim, blue-white hued star with an apparent visual magnitude of 5.30. It is moving further away from the Earth with a heliocentric radial velocity of 21 km/s.

Its equilibrium temperature is 181 Kelvin. A major detrimental factor which may prevent life from forming and it being an inhabitable planet is the fact that Gliese 581 is a variable star.

WASP-14 or BD+22 2716 is a star in the constellation Boötes. The SuperWASP project has observed and classified this star as a variable star, perhaps due to the eclipsing planet.

W Coronae Borealis (W CrB) is a Mira-type long period variable star in the constellation Corona Borealis. Its apparent magnitude varies between 7.8 and 14.3 over a period of 238 days.

6 Cas A is an α Cyg variable, pulsating erratically between 5.34 and 5.45. The strongest period detected in one study was 37 days. It has the variable star designation V566 Cassiopeiae.

Edwin Hubble discovers a Cepheid variable star in the "Andromeda Nebula" and proves that Andromeda and other nebulas are galaxies far beyond our own. By 1925, he produces a classification system for galaxies.

Nova Reticuli 2020 is a naked eye nova in the constellation Reticulum discovered on July 15, 2020. Previously it was known as a VY Sculptoris type object with variable star designation MGAB-V207.

Pulsations of S Orionis, showing dust production and masers (ESO) The descriptive term long-period variable star refers to various groups of cool luminous pulsating variable stars. It is frequently abbreviated to LPV.

RS Persei is a red supergiant variable star located in the Double Cluster in Perseus. The star's apparent magnitude varies from 7.82 to 10.0, meaning it is never visible to the naked eye.

In 1929, Young identified the comet 31P/Schwassmann–Wachmann with an object that had been misidentified as the minor planet "Adelaide" (A904 EB) in 1904. Young had a pronounced interest in variable stars and corresponded on the subject with Edward Charles Pickering, director of the Harvard College Observatory. She was one of the eight founding members of the American Association of Variable Star Observers (AAVSO) and contributed over 6,500 variable star observations to the organization. She was elected the organization's President in 1923.

12 Ophiuchi is a variable star in the constellation Ophiuchus. No companions have yet been detected in orbit around this star, and it remains uncertain whether or not it possesses a dust ring. This star is categorized as a BY Draconis variable, with variable star designation V2133. The variability is attributed to large-scale magnetic activity on the chromosphere (in the form of starspots) combined with a rotational period that moved the active regions into (and out of) the line of sight.

104 Herculis is a solitary variable star located around 560 light years away from the Sun in the northern constellation of Hercules. It has the variable star designation V669 Herculis and the Bayer designation A Herculis, while 104 Herculis is the Flamsteed designation. This object is visible to the naked eye as a dim, red-hued point of light with a baseline apparent visual magnitude of 4.96. It is moving closer to the Earth with a heliocentric radial velocity of −1.2 km/s.

Mira (), designation Omicron Ceti (ο Ceti, abbreviated Omicron Cet, ο Cet), is a red giant star estimated to be 200–400 light-years from the Sun in the constellation Cetus. ο Ceti is a binary stellar system, consisting of a variable red giant (Mira A) along with a white dwarf companion (Mira B). Mira A is a pulsating variable star and was the first non-supernova variable star discovered, with the possible exception of Algol. It is the prototype of the Mira variables.

HD 111395 is a single, variable star in the northern constellation of Coma Berenices. It has the variable star designation LW Com, short for LW Comae Berenices; HD 111395 is the Henry Draper Catalogue designation. The star has a yellow hue and is just bright enough to be barely visible to the naked eye with an apparent visual magnitude that fluctuates around 6.29. Based upon parallax measurements, it is located at a distance of 55.8 light years from the Sun.

Light echo of V838 Mon as imaged April 30, 2002 On January 6, 2002, an unknown star was seen to brighten in the constellation Monoceros, the Unicorn. Being a new variable star, it was designated V838 Monocerotis, the 838th variable star of Monoceros. The initial light curve resembled that of a nova, an eruption that occurs when enough hydrogen gas has accumulated on the surface of a white dwarf from its close binary companion. Therefore, it was also designated Nova Monocerotis 2002.

101 Virginis is a red giant variable star in the Boötes constellation, currently on the asymptotic giant branch. It was originally catalogued as 101 Virginis by Flamsteed due to an error in the position. When it was confirmed as a variable star, it was actually within the border of the constellation Bootes and given the name CY Boötis. The variability is not strongly defined but a primary period of 23 days and a secondary period of 340 days have been reported.

It is suspected of being a Delta Scuti variable star. The companion is a spectral class M0.5V red dwarf star with absolute magnitude 9.80. It is a UV Ceti variable star that undergoes random increases in luminosity. This star is currently separated from the primary by an angle of 6.6 arcseconds, which indicates an orbit with a semimajor axis whose expected value is 206 AU. Alpha Caeli is approximately 65.7 light years from Earth and is an estimated 900 million years old.

Visual observations of variable stars and plotting the light curves. These observations are reporting to the organizations- AAVSO. Khagol Vishwa has formed a special Variable Star Section (VSS) for detailed study in this field.

IRAS 08544−4431 is a binary system surrounded by a dusty ring in the constellation of Vela. The system contains an RV Tauri variable star and a more massive but much less luminous companion.

Both stars appear to be deficient in helium. The primary is a helium variable star while the companion is a mercury-manganese star. The variability of both stars aligns favorably with the orbital period.

The variable star designation for HD 209458 is V376 Pegasi. It is the prototype of the variable class "EP" in the General Catalogue of Variable Stars, defined as stars showing eclipses by their planets.

BD Phoenicis is a variable star in the constellation of Phoenix. From parallax measurements by the Gaia spacecraft, it is located at a distance of from Earth. Its absolute magnitude is calculated at 1.5.

Samus et al. (2017) classify it as a slowly pulsating B-type variable star (SPB), which ranges from magnitude 5.84 down to 5.87 with a rotationally-modulated period of 2.72945 days. Briquet et al.

HD 158220 is a giant Be star in the southern constellation of Ara. This is a pulsating variable star that changes brightness by an amplitude of 0.030 magnitude over a period of 1.15 days.

In 1999, 10 Persei was given the variable star designation V554 Persei, after being identified as varying in Hipparcos photometry. Its brightness varies by less than a tenth of a magnitude with no clear period.

DS Crucis (HR 4876, HD 111613) is a variable star near the open cluster NGC 4755, which is also known as the Kappa Crucis Cluster or Jewel Box Cluster. It is in the constellation Crux.

Photometry of CPD−57°2874 suggests that it is variable with an amplitude of perhaps 0.2 magnitudes. It has not been formally classified as a variable star and the cause of the variations is unclear.

V957 Scorpii is a variable star in the constellation of Scorpius. It is a blue straggler in the open cluster Messier 7, a star that is unexpectedly hot compared to other members of the cluster.

S Arae (S Ara) is an RR Lyrae-type pulsating variable star in the constellation of Ara. It has an apparent visual magnitude which varies between 9.92 and 11.24, and it exhibits the Blazhko effect.

V533 Carinae (V533 Car, y Car, y Carinae) is a white A-type supergiant variable star with a mean apparent magnitude of +4.59 in the constellation Carina. It is over 10,000 light years from Earth.

U Monocerotis (U Mon) is a pulsating variable star and spectroscopic binary in the constellation Monoceros. The primary star is an RV Tauri variable, a cool luminous post-AGB star evolving into a white dwarf.

RS Persei is classified as a semiregular variable star, with its brightness varying from magnitude 7.82 to 10.0 over 245 days, Detailed studies show that it also pulsates with a long secondary period of days.

This orange-hued giant shines with 1,330 times the luminosity of the Sun. It is a low-amplitude photometric variable star showing a typical change of roughly 0.0054 in magnitude over a 24-hour period.

It is classified as an Alpha Cygni type variable star and its brightness varies from magnitude 4.19m to 4.23m. Its companion, CS Camelopardalis B, is a magnitude 8.7m star located 2.9 arcseconds from the primary.

Observations of the open cluster NGC 7419 in 1954 showed that four of its members were luminous red stars, most likely red supergiants. In addition, an unusually red star was found to be variable and probably an even more luminous supergiant. This star was given the variable star designation MY Cephei in 1973 in the 59th name- list of variable stars. MY Cephei is classified as semiregular variable star of sub-type SRc, indicating it is a cool supergiant, although its pulsational period is not known.

Through October 2004, she served as a council member of the American Association of Variable Star Observers for 4 terms, a senior vice president for 2 terms, president for 2 years, and an ex-president for 2 years. Willson was also on the Board of Directors of the Association of Universities for Research in Astronomy from 1989-2002. She has received many awards including the Annie Jump Cannon award in 1980 and the 40th Merit Award from the American Association of Variable Star Observers in 2008.

119 Tauri has a spectral class of M2 and a luminosity class of Iab-Ib, intermediate between an intermediate- luminosity supergiant and a less luminous supergiant. It is approximately 1,800 light years from Earth, and with a colour index of +2.07 it is one of the reddest naked eye stars in the night sky. It is a similar star to Betelgeuse although redder and more distant. 119 Tauri is classified as a semiregular variable star and has been given the variable star designation CE Tauri.

W Andromedae is a variable star in the constellation of Andromeda. It is classified as a Mira variable of S-type star, International Variable Star Index, Accessed 2012-01-19 and varies from an apparent visual magnitude of 14.6 at minimum brightness to a magnitude of 6.7 at maximum brightness, with a period of approximately 397.3 days.W 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.

It also has the Bright Star Catalogue number 1457, the HD number 29139, and the Hipparcos catalogue number 21421, mostly seen in scientific publications. It is a variable star listed in the General Catalogue of Variable Stars, but it is listed using its Bayer designation and does not have a separate variable star designation. Aldebaran and several nearby stars are included in double star catalogues such as the Washington Double Star Catalog as WDS 04359+1631 and the Aitken Double Star Catalogue as ADS 3321\.

Chary discovered the variable star R Reticuli in 1867. He was the first Indian in modern history to make a significant astronomical discovery. Chary noted that the star which was observed by astronomer T. Moottooswamy Pillai with a Meridian Circle on 9 February 1864 was not visible when observed in January 1866 but could be spotted on 18 January 1867. Some sources also attribute the discovery of another variable star V Cephei or U Cephei to him but same has not been confirmed by the Madras Observatory.

21 Comae Berenices is a variable star in the northern constellation of Coma Berenices. It has the variable star designation UU Comae Berenices, while 21 Comae Berenices is the Flamsteed designation. According to R. H. Allen, English orientalist Thomas Hyde attributed the ancient title Kissīn to this star, a name that comes from a climbing plant – either bindweed or dog rose. This star has a white hue and is just visible to the naked eye with an apparent visual magnitude that fluctuates around 5.47.

No significant brightness changes have been detected in WR 31a, but it has been listed as a candidate luminous blue variable because of its luminosity, temperature, and mass loss properties. Van Genderen catalogued it as a dormant or ex-LBV because of the lack of characteristic LBV variations.Vizie database entry Possible small brightness changes have been seen in All Sky Automated Survey (ASAS) data, WR 31a is included as a variable star in the International Variable Star Index, although not in the General Catalogue of Variable Stars.

HD 49976 is a variable star in the constellation of Monoceros (the Unicorn). It has the variable star designation V592 Monocerotis, while HD 49976 is the identifier from the Henry Draper Catalogue. It has a white hue and is near the lower limit of visibility to the naked eye, having an apparent visual magnitude that fluctuates from 6.16 down to 6.32 with a 2.976 day period. Based upon parallax measurements, it is located at a distance of approximately 337 light years from the Sun.

Iota Herculis (ι Herculis, ι Her) is a fourth-magnitude variable star system in the constellation Hercules, consisting of at least four stars all about away. The brightest is a β Cephei variable, a pulsating star.

In approximately 9-20 billion years, RR Caeli will likely become a cataclysmic variable star due to the period's gradual shortening, leading to increasing rates of transfer of hydrogen to the surface of the white dwarf.

Michiel Daniel Overbeek (15 September 1920 in Ermelo, Mpumalanga, South Africa – 19 July 2001 in Johannesburg), also known as Danie Overbeek, was a South African amateur astronomer and one of the most prolific variable star observers.

PX Andromedae (often abbreviated to PX And) is an eclipsing cataclysmic variable star in the constellation Andromeda. It has been classified as a SW Sextantis variable, and its apparent visual magnitude varies between 14.04 and 17.

RW Cygni is a semiregular variable star in the constellation Cygnus, about a degree east of 2nd magnitude γ Cygni. Its apparent magnitude varies between 8.05 and 9.70 and its spectral type between M3 and M4.

V538 Carinae is a variable star in the constellation of Carina, and a possible red supergiant. If this star replaced our sun in our solar system, its photosphere would at least engulf the orbit of Mars.

Eta Geminorum (η Geminorum, abbreviated Eta Gem, η Gem), formally named Propus , is a triple star system in the constellation of Gemini. It is a naked-eye variable star around 380 light years from the Sun.

V4650 Sagittarii (qF362) is a luminous blue variable star (LBV) in the constellation of Sagittarius. Located some 25,000 light years away, the star is positioned on the edge of a starburst cluster known as the Quintuplet cluster.

A Blue large-amplitude pulsator (BLAP) is a proposed class of pulsating variable star. They are extremely rare, with only 14 being known after examining around a billion stars from the Optical Gravitational Lensing Experiment (OGLE) survey.

V382 Carinae, also known as x Carinae (x Car), is a yellow hypergiant in the constellation Carina. It is a G-type star with a mean apparent magnitude of +3.93, and a variable star of low amplitude.

HD 224801, also known as CG Andromedae, is an Alpha² Canum Venaticorum variable star in the constellation Andromeda. Located approximately away, the star varies between apparent magnitudes 6.32 and 6.42 over a period of approximately 3.74 days.

24 Ursae Majoris is a variable star in the northern circumpolar constellation of Ursa Major, located 101.5 light-years from the Sun. It has the variable star designation DK Ursae Majoris and the Bayer designation d Ursae Majoris; 24 Ursae Majoris is the Flamsteed designation. This object is visible to the naked eye as a faint, yellow-hued star with an apparent visual magnitude of 4.54. It is moving closer to the Earth with a heliocentric radial velocity of −27 km/s, and is expected to come as close as in around 879,000 years.

The distance to this cluster has also been difficult to determine, again, owing to the absorption. Estimates for the Distance modulus range from 12.5 to 14.5. Due to the similarities between NGC 7142 and NGC 188 in both age and density, some astronomers have speculated that NGC 7142 should be home to a high number of a rare type of variable star known as W UMa since NGC 188 has a high number. Crinklaw & Talbert conducted a search for such stars in 1991, but their study only revealed one variable star.

It is a variable star with a magnitude that varies between 2.76m and 2.90m. The General Catalogue of Variable Stars classifies it only as BE, indicating that it is a variable Be star but not obviously a Gamma Cassiopeiae variable. The International Variable Star Index defines it as GCAS + LERI, showing both rapid periodic variation and slow irregular eruptions. Alpha Arae has a visual companion star, CCDM J17318-4953B, located approximately 50 arcseconds away along a position angle of 168°, with an apparent visual magnitude of about 11.

It began life as a hot blue main sequence star, but now is a large cool asymptotic giant branch star with a degenerate carbon-oxygen core. It is a semi-regular variable star that has its brightness change by 0.2 magnitudes over an ill- defined period. Delta2 Lyrae was once thought to form a visual binary with the star Delta1 Lyrae, but it does not, only appearing to do so if seen from earth's direction. δ2 Lyrae is a variable star, probably a semiregular variable. It has a magnitude range of 4.22 to 4.33.

R Sagittae is an RV Tauri variable star in the constellation Sagitta that varies from magnitude 8.0 to 10.5 in 70.77 days. It is a post-AGB low mass yellow supergiant that varies between spectral types G0Ib and G8Ib as it pulsates. Its variable star designation of "R" indicates that it was the first star discovered to be variable in the constellation. It was discovered in 1859 by Joseph Baxendell, though classified as a semi regular variable until RV Tauri variables were identified as a distinct class in 1905.

This minor planet was named after the American Association of Variable Star Observers (AAVSO), an astronomical pro-am organization that promotes the study of variable stars to both amateur and professional astronomers, maintaining the largest database of variable star observations in the world. AAVSO was founded in 1911 by amateur astronomer William Tyler Olcott (1873–1936), based on a suggestion by Edward Charles Pickering's (1846–1919), after whom the minor planet 784 Pickeringia is named. The official naming citation was published by the Minor Planet Center on 1 May 2003 .

19 Lyrae is a single variable star located approximately 940 light years away from the Sun in the northern constellation of Lyra. It has the variable star designation V471 Lyr, while 19 Lyrae is the Flamsteed designation. This object is just bright enough to be visible to the naked eye, appearing as a dim, blue-white star with a baseline apparent visual magnitude of 5.93. It is moving closer to the Earth with a heliocentric radial velocity of −30 km/s, and may come as close as around 8.5 million years from now.

RW Cephei is a hypergiant variable star in the constellation Cepheus, at the edge of the Sharpless 132 HII region and close to the small open cluster Berkeley 94. One of the largest stars known, RW Cephei's radius is more than 1,000 times that of the Sun (), thus larger than the orbit of Jupiter. RW Cephei is also a semi-regular variable star of type SRd, meaning that it is a slowly varying yellow giant or supergiant. The visual magnitude range is from 6.0 to 7.3, while the photographic range is from 8.6 - 10.7.

This is a Be star as shown by the 'e' suffix, which means it has variable emissions in its hydrogen spectral lines. This emission can be modeled by a decretion disk of gas that has been ejected from the star and now follows a near Keplerian orbit around the central body. Finally it is slightly variable, and classified as a Gamma Cassiopeiae variable star with multiple periods of variability. The International Variable Star Index lists Eta Centauri as both a Gamma Cassiopeiae variable and a Lambda Eridani variable.

WR 140 is listed as a Wolf-Rayet variable star, and has been given the variable star designation V1687 Cyg in the General Catalogue of Variable Stars, whose visual brightness varies only very slightly. Interest with this WR 140 system is principally observing the infrared light fluctuations during the component's orbit, being extensively studied because of its episodic dust formation. It is now regarded as the prototype colliding-wind binary. Shortly after periastron passage every eight years, the infrared brightness increases dramatically and then slowly drops again over a period of months.

The Luyten 726-8 system is approximately from Earth's Solar System, in the constellation Cetus, and is thus the seventh-closest star system to Earth. Its own nearest neighbor is Tau Ceti, away from it. If R_v=+29 km/s then approximately 28,700 years ago Luyten 726-8 was at its minimal distance of 2.21 pc (7.2 ly) from the Sun. Luyten-726-8A was later found to be a variable star and given the variable star designation BL Ceti. It is a red dwarf of spectral type M5.5e.

HD 149989 is a single, variable star in the southern constellation of Ara, located near the western constellation border with Norma. It has the variable star designation V872 Arae, while HD 149989 is the identifier from the Henry Draper Catalogue. This is a dim star near the lower limit of visibility to the naked eye with an apparent visual magnitude that fluctuates around 6.30. It is located at a distance of 167 light years from the Sun based on parallax, and is drifting further away with a radial velocity of 46 km/s.

AM Herculis is a binary variable star located in the constellation Hercules. This star, along with the star AN Ursae Majoris, is the prototype for a category of cataclysmic variable stars called polars, or AM Her type stars.

GP Andromedae (often abbreviated to GP And) is a Delta Scuti variable star in the constellation Andromeda. It is a pulsating star, with its brightness varying with an amplitude of 0.55 magnitudes around a mean magnitude of 10.7.

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.

AE Aurigae is a blue-hued main-sequence variable star. It is normally of magnitude 6.0, but its magnitude varies irregularly. AE Aurigae is associated with the 9-light-year-wide Flaming Star Nebula (IC 405), which it illuminates.

It is a candidate variable star of unknown type, showing an amplitude variation of 0.0115 magnitude with a frequency of 0.47645 times per day, or one cycle per 2.1 days. X-ray emission has been detected from this system.

GR Andromedae (often abbreviated to GR And) is a variable star in the constellation Andromeda. Its apparent visual magnitude varies between 6.87 and 6.95 in a cycle of 518.2 days. It is classified as an α2 Canum Venaticorum variable.

HN Andromedae (often abbreviated to HN And) is a variable star in the constellation Andromeda. Its apparent visual magnitude varies between 6.67 and 6.76 in a cycle of 69.51 days. It is classified as an α2 Canum Venaticorum variable.

An ancient Egyptian calendar of lucky and unlucky days composed some 3,200 years ago may be the oldest preserved historical document of the discovery of a variable star, the eclipsing binary Algol. Of the modern astronomers, the first variable star was identified in 1638 when Johannes Holwarda noticed that Omicron Ceti (later named Mira) pulsated in a cycle taking 11 months; the star had previously been described as a nova by David Fabricius in 1596. This discovery, combined with supernovae observed in 1572 and 1604, proved that the starry sky was not eternally invariable as Aristotle and other ancient philosophers had taught. In this way, the discovery of variable stars contributed to the astronomical revolution of the sixteenth and early seventeenth centuries. The second variable star to be described was the eclipsing variable Algol, by Geminiano Montanari in 1669; John Goodricke gave the correct explanation of its variability in 1784.

The supergiant component W Sgr Aa1 is a variable star which pulsates regularly between magnitudes 4.3 and 5.1 every 7.59 days. During the pulsations, that temperature and spectral type also vary. It is classified as a Classical Cepheid (δ Cephei) variable.

V1057 Cygni (V1057 Cyg) is a FU Orionis-type variable star in the constellation of Cygnus. It has a spectral type of F and an apparent visual magnitude of approximately 11.660. It was the second FU Orionis-type variable discovered.

Thomas Espin noted the possible variability of this star in 1895. Williamina Fleming, in 1906, was examining photographic plates taken for the purpose of creating the Henry Draper Catalogue when she independently discovered and confirmed it as a variable star.

HP Lyrae (HP Lyr) is a variable star in the constellation Lyra, with a visual magnitude varying 10.2 and 10.8. It is likely to be an RV Tauri variable, an unstable post-AGB star losing mass before becoming a white dwarf.

U Equulei (U Equ / IRAS 20547 +0247) is a variable star in the Equuleus constellation with an apparent magnitude of +14.50 in the B band. It lies at an estimated distance of 5,000 light-years (1,500 parsecs ) from the Solar System.

G 185-32, also known by the variable star designation PY Vulpeculae, is a white dwarf in the constellation Vulpecula. Located approximately distant, the stellar remnant is a ZZ Ceti variable, varying by 0.02 apparent magnitudes from the mean of 13.00.

HV 2112 is a cool luminous variable star in the Small Magellanic Cloud. Until 2018, it was considered to be the most likely candidate for a Thorne–Żytkow object, but it is now thought to be an asymptotic giant branch star.

Symbiotic stars are all binaries and so the term symbiotic binary is synonymous. Many are variable and the term symbiotic variable or symbiotic variable star is sometimes also used synonymously, but more commonly is used only for Z Andromedae variable stars.

It is assumed to be of similar age to its primary. γ Cephei is catalogued as a suspected variable star with a brightness range between magnitudes 3.18 and 3.24, based on its inclusion in an 1884 list of suspected variable stars.

Sigma Canis Majoris (σ Canis Majoris, abbreviated Sigma CMa, σ CMa), also named Unurgunite , is a variable star in the southern constellation of Canis Major. It is approximately from the Sun and has an average apparent visual magnitude of +3.41.

CK Carinae (CK Car / HD 90382 / SAO 238038) is a variable star in the constellation Carina, the keel of Argo Navis. It is a member of the star association Carina OB1-D, at a distance of around or . Classified as a semiregular variable star, CK Carinae's brightness varies between apparent magnitudes +7.2 and +8.5 with a period of approximately 525 days. It has a Gaia Data Release 2 parallax of , which implies a distance of around , and is thought to be a member of the Carina OB1-D stellar association which is at a distance of about .

NGC 2363 as seen by the Hubble Space Telescope. The luminous blue variable star NGC 2363-V1 is the isolated bright star above and left of center. (Credit NASA) In 1996, Robert was credited, along with two other astrophysicists, for the discovery of a new luminous blue variable star called NGC 2363-V1, which is located in the star-forming region NGC 2363, at the far southwestern part of the irregular galaxy called NGC 2366 in the Camelopardalis constellation, in the northern celestial hemisphere. It is almost 11 million light years away from the Earth's galaxy.

NGC 7822 is a young star forming complex in the constellation of Cepheus. The complex encompasses the emission region designated Sharpless 171, and the young cluster of stars named Berkeley 59. The complex is believed to be some 800–1000 pc distant,Majaess D., Turner D., Lane D., Moncrieff K. (2008). The Exciting Star of the Berkeley 59/Cepheus OB4 Complex and Other Chance Variable Star Discoveries, Journal of the American Association of Variable Star Observers, vol. 36, no. 1, p. 90Pandey et al.(2008).Stellar contents and star formation in the young star cluster Be 59, MNRAS, Volume 383, Issue 3, pp.

10 Canis Majoris is a single variable star in the southern constellation of Canis Major, located roughly 1,800 light years away from the Sun. It has the variable star designation FT Canis Majoris; 10 Canis Majoris is the Flamsteed designation. This body is visible to the naked eye as a faint, blue-white hued star with a baseline apparent visual magnitude of 5.23. It is moving away from the Earth with a heliocentric radial velocity of +34 km/s. This is a massive Be star with a stellar classification of B2 V, matching a B-type main-sequence star.

26 Canis Majoris is a variable star in the southern constellation of Canis Major, located around 1,010 light years away from the Sun. It has the variable star designation MM Canis Majoris; 26 Canis Majoris is the Flamsteed designation. This object is visible to the naked eye as a dim, blue-white hued star with a baseline apparent visual magnitude of 5.89. It is moving further from the Earth with a heliocentric radial velocity of +22 km/s. With a stellar classification of B2 IV/V, it appears as a B-type main-sequence star intermixed with traits of an evolving subgiant star.

UY Scuti was first catalogued in 1860 by German astronomers at the Bonn Observatory, who were completing a survey of stars for the Bonner Durchmusterung Stellar Catalogue. It was designated BD-12°5055, the 5,055th star between 12°S and 13°S counting from 0h right ascension. On detection in the second survey, the star was found to have changed slightly in brightness, suggesting that it was a new variable star. In accordance with the international standard for designation of variable stars, it was called UY Scuti, denoting it as the 38th variable star of the constellation Scutum.

DS Crucis is a variable star with an amplitude of about 0.05 magnitudes. It was found to be variable from the photometry performed by the Hipparcos satellite. The variability type is unclear but it is assumed to be an α Cygni variable.

As of 2008, magnitude 10.32 component C lies at an angular separation of 86.90″, while magnitude 10.64 component D is at a separation of 105.0″. Mu CMa should not be confused with the 9th magnitude variable star MU CMa located near NGC 2360.

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.

AH Scorpii (abbreviated to AH Sco) is a red supergiant variable star located in the constellation Scorpius. It is one of the largest stars known by radius and is also one of the most luminous red supergiant stars in the Milky Way.

LY Aurigae is a multiple star system in the constellation Auriga. It is an eclipsing binary variable star, dropping in brightness by 0.7 magnitudes every 4 days. The system is around a thousand light years away in the Auriga OB1 stellar association.

Kyung Hee Astronomical Observatory is an astronomical observatory owned and operated by Kyung Hee University. It is located in Giheung-gu, Yongin, South Korea. It was the first observatory in the nation to discover a variable star, later named the Kyung Hee Star.

Shortly afterwards it received its variable star designation of DL Crucis. A later detailed statistical analysis of the same data found periods of 3.650 and 3.906 days, as well as a first harmonic pulsation, with a maximum brightness range of 0.11 magnitudes.

HD 90089 is a suspected variable star in the constellation Camelopardalis. An infrared excess has been detected around this star, most likely indicating the presence of a circumstellar disk at a radius of 145 AU. The temperature of this dust is 30 K.

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.

Gay was on the Council (Board of Directors) for the American Association of Variable Star Observers, as well as its Educational Committee Chair. Gay was co-chair of the United States new media efforts with regard to the International Year of Astronomy, 2009.

Two bright stars Phi Cassiopeiae (magnitude 5) and HD 7902 (magnitude 7) can be imagined as eyes. The next brightest star is the red supergiant variable star V466 Cassiopeiae. The cluster features a rich field of about 150 stars of magnitudes 9-13.

The life of such massive stars is very short. Despite its advanced evolutionary state, V419 Cephei is only 10 million years old. Billed as an irregular variable star of type LC, V419 Cephei's brightness varies between magnitudes 6.54 and 6.89 with no apparent periodicity.

This is a class of variable star whose variability comes from starspots on the stars' surfaces. HR 7578 also has a common proper motion companion, 2MASS J19542064−2356398. It is a red dwarf that is at least 580 astronomical units from the central star system.

RY Sagittarii is a yellow supergiant and an R Coronae Borealis type variable star in the constellation Sagittarius. Although it ostensibly has the spectrum of a G-type star, it differs markedly from most in that it has almost no hydrogen and much carbon.

This star type varies in luminosity due to non-radial pulsations. Its apparent magnitude varies from 4.93 to 5.03 over a period of 1.25804 days. For that reason it has been given the variable star designation V398 Aurigae. 9 Aurigae is a multiple star system.

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.

By 2004, robotic observations accounted for an overwhelming percentage of the published scientific information on asteroid orbits and discoveries, variable star studies, supernova light curves and discoveries, comet orbits and gravitational microlensing observations. All early phase Gamma ray burst observations were carried by robotic telescopes.

V394 Aurigae is a semi-regular variable star in the constellation Auriga. It varies between magnitudes 6.01 and 6.11. Located around 730 light-years distant, it shines with a luminosity approximately 1075 times that of the Sun and has a surface temperature of 3589 K.

TU Andromedae (TU And) is a variable star of the Mira type in the constellation Andromeda. Like all the stars of this kind, TU And is a cool asymptotic giant branch star. It has a spectral type M5e. The period is stable at 316.8 days.

Nothing is known about the companion. Two degrees southeast of Alpha is the red-hued Nu Tucanae, of spectral type M4III and lying around 290 light-years distant. It is classified as a semiregular variable star and its brightness varies from magnitude +4.75 to +4.93.

LS I +61 303 varies slightly at optical wavelengths, but measurements going back to 1887 show no obvious period. It also shows regular X-ray outbursts coinciding with its orbital period, and strong radio variability. It was given the variable star designation V615 Cassiopeiae.

V1017 Sagittarii is a cataclysmic variable star system in the constellation Sagittarius. It first erupted in 1919, reaching magnitude 7. Its other eruptions in 1901, 1973 and 1991 only reached magnitude 10, leading it to be reclassified from a recurrent nova to a dwarf nova.

KY Cygni is a variable star with a large amplitude but no clear periodicity. At times, it varies rapidly, at others it is fairly constant for long periods. The photographic magnitude range is given as 13.5 - 15.5, while a visual range is 10.60 - 11.74.

Light curve of δ Cephei showing magnitude versus pulsation phase Graphs of the apparent magnitude of a variable star over time are commonly used to visualise and analyse their behaviour. Although the categorisation of variable star types is increasingly done from their spectral properties, the amplitudes, periods, and regularity of their brightness changes are still important factors. Some types such as Cepheids have extremely regular light curves with exactly the same period, amplitude, and shape in each cycle. Others such as Mira variables have somewhat less regular light curves with large amplitudes of several magnitudes, while the semiregular variables are less regular still and have smaller amplitudes.

He now holds the world record for the greatest number of such events discovered by any individual in history. More recently the BAA has worked increasingly with international partners. Modern communications allow astronomers in different time zones around the world to hand over the monitoring of variable stars and planetary weather systems to colleagues on other continents as the Sun comes up, resulting in a 24-hour watch on the sky. For example, the Association's Variable Star Section works closely with the American Association of Variable Star Observers, meanwhile its Jupiter Section works with a global network of planetary observers through the JUPOS collaboration.

Metzger noticed one object that had increased in luminosity, but he assumed it was a variable star rather than the GRB afterglow. Titus Galama and Paul Groot, members of a research team in Amsterdam led by Jan van Paradijs, compared images taken by the WIYN Telescope on May 8 and the William Herschel Telescope on May 9\. They were also unable to find any light sources which had faded during that time. After discovering the burst's X-ray afterglow, the BeppoSAX team provided a more accurate localization, and what Metzger had assumed to be a variable star was still present in this smaller error box.

As a prominent infrared source, it appears in the Two Micron All-Sky Survey catalogue as 2MASS J16292443-2625549 and the Infrared Astronomical Satellite (IRAS) Sky Survey Atlas catalogue as IRAS 16262–2619. It is also catalogued as a double star WDS J16294-2626 and CCDM J16294-2626. Antares is a variable star and is listed in the General Catalogue of Variable Stars but as a Bayer-designated star it does not have a separate variable star designation. Its traditional name Antares derives from the Ancient Greek , meaning "rival to-Ares" ("opponent to-Mars"), due to the similarity of its reddish hue to the appearance of the planet Mars.

49 Camelopardalis is a variable star in the northern circumpolar constellation of Camelopardalis, located 313 light years from the Sun based on parallax measurements. It has the variable star designation BC Camelopardalis; 49 Camelopardalis is the Flamsteed designation. This star is a challenge to view with the naked eye, having a baseline apparent visual magnitude of 6.50. It is moving away from the Earth with a heliocentric radial velocity of +6.5 km/s. This is a magnetic chemically peculiar star with a stellar classification of A7VpSrCrEuSiKsn, indicating it is an A-type main-sequence star with overabundances of various elements including strontium and europium, as well as broad, "nebulous" lines.

SU Andromedae is a carbon star in the constellation of Andromeda. It is a variable star classified as a slow irregular pulsating supergiant, and varies from an apparent visual magnitude of 8.5 at minimum brightness to a magnitude of 8.0 at maximum brightness with no clear period.

XX Trianguli is a variable star in the constellation of Triangulum. It is classified as a RS Canum Venaticorum variable orange giant with spectral type K0III. XX Trianguli is quite notable for having a huge starspot larger than the diameter of the Sun, discovered using Doppler imaging.

Light curve of eclipsing dwarf nova HT Cassiopeia during outburst, showing eclipses and SU Ursae Majoris type superhumps In astronomy, a superhump is a periodic brightness variation in a cataclysmic variable star system, with a period within a few percent of the orbital period of the system.

OGLE-TR-10 is a distant, magnitude 16 star in the constellation of Sagittarius. It is located near the Galactic Center. This star is listed as an eclipsing type variable star with the eclipse due to the passage of the planet as noted in the discovery papers.

In Johann Bayer's 17th-century star atlas, the Uranometria, it was suggested that Alpha, Beta and Gamma Cygni formed the pole of the Christian Cross, while Delta and Epsilon formed the cross beam. The variable star P Cygni was then considered to be the body of Christ.

It is a weak X-ray emitter with an X-ray luminosity of about . This emission is most likely coming from transient loops of plasma in Iota Aurigae's outer atmosphere, which have a temperature of around . This is a suspected variable star, although this variability remains unconfirmed.

RS Puppis (or RS Pup) is a Cepheid variable star around away in the constellation of Puppis. It is one of the biggest and brightest known Cepheids in the Milky Way galaxy and has one of the longest periods for this class of star at 41.5 days.

She collaborated on variable star observations with Whitney from 1909 to 1911. In 1915, she authored the authoritative textbook Introduction to the Study of Variable Stars. She became a fellow of the Royal Astronomical Society in 1922. She died on 9 February 1936 in New York City.

Farnsworth was elected to the membership of the American Astronomical Society in 1917. She returned to the astronomy department at Mount Holyoke after completing her doctorate. She taught astronomy courses, including darkroom skills. From 1929-1931 she was president of the American Association of Variable Star Observers.

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.

RT Normae is an R Coronae Borealis type variable star in the constellation Norma. It has a baseline magnitude of 9.8, dropping down to 14.7 at its minima. It has less than 55% the mass of the Sun and an effective (surface) temperature of around 7000 K.

Three nonfiction books and two poems have been published posthumously. For Us, the Living: A Comedy of Customs was published posthumously in 2003; Variable Star, written by Spider Robinson based on an extensive outline by Heinlein, was published in September 2006. Four collections have been published posthumously.

49 Cancri is a variable star. Its brightness changes from magnitude 5.58 to 5.71 every seven days. It is classified as an α2 Canum Venaticorum variable, a class of magnetic chemically peculiar stars. The brightness changes are thought to correspond to the rotation of the star.

"Sci-fi collaboration made in heaven". Winnipeg Free Press, via Newspaper Archives. February 03, 2008 - Page 36"Variable Star". Publishers Weekly, review Robinson had previously written of his admiration for Heinlein in his 1980 essay "Rah, Rah, R.A.H.!" in the 1998 "Mentors", and in his book The Free Lunch.

The novel reflects the very different writing styles of both Heinlein and Robinson; reviews of the books were mixed, praising Robinson's handling of a difficult task and the lively story, but criticizing the unlikely plot twists and trite romantic scenes."VARIABLE STAR". SF Reviews, 2006 by Thomas M. Wagner.

The Sun is a weakly variable star, and its actual luminosity therefore fluctuates. The major fluctuation is the eleven-year solar cycle (sunspot cycle) that causes a quasi-periodic variation of about ±0.1%. Other variations over the last 200–300 years are thought to be much smaller than this.

It is a suspected variable star of unknown type that has been measured ranging in brightness from magnitude 5.01 down to 5.26 in the infrared I band. The star is radiating 496 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,267 K.

The Coronet cluster, about 554 light years (170 parsecs) away at the edge of the Gould Belt, is also used in studying star and protoplanetary disk formation. R Coronae Australis is an irregular variable star ranging from magnitudes 9.7 to 13.9. Blue-white, it is of spectral type B5IIIpe.

NS Puppis (NS Pup) is an irregular variable star in the constellation Puppis. Its apparent magnitude varies between 4.4 and 4.5. NS Puppis is a naked eye star, given the h1 and the Bright Star Catalogue number 3225. It was considered to be a stable star until 1966.

NGC 559 (also known as Caldwell 8) is an open cluster and Caldwell object in the constellation Cassiopeia. It shines at magnitude +9.5. Its celestial coordinates are RA , dec . It is located near the open cluster NGC 637, and the bright magnitude +2.2 irregular variable star Gamma Cassiopeiae.

HD 316285 is listed in the General Catalogue of Variable Stars as a variable Be star with a range of about one tenth of a magnitude. The International Variable Star Index classifies it as an S Doradus variable and it is considered to be a candidate luminous blue variable.

74 Aquarii (abbreviated 74 Aqr) is a triple star system in the constellation of Aquarius. 74 Aquarii is its Flamsteed designation and it also bears the variable star designation HI Aquarii. The combined apparent visual magnitude is 5.8 and it is located at a distance of from Earth.

The spatial dimension of this cluster is about across. It has an estimated mass of , of which about 24% is interstellar matter. A Delta Cephei type variable star designated U Sagittarii is a member of this cluster, as are two red giants, one of which is a binary system.

However, their investigation only spanned two days, which did not afford enough data points to determine the type of variable. Roughly two more nights of data were appended to the beginning of the Crinklaw & Talbert study but have still not given enough information to classify the variable star.

R Doradus (HD 29712 or P Doradus) is a red giant variable star in the far- southern constellation Dorado. Its distance from Earth is . Having a uniform disk diameter of arcsec, it is thought to be the extrasolar star with the largest apparent size as viewed from Earth.

V1073 Scorpii (V1073 Sco) is a variable star in the constellation Scorpius. It also has a non-Greek Bayer designation of k Scorpii. V1073 Sco has a 14th magnitude companion. V1073 Sco is an α Cygni variable, a supergiant which pulsates erratically on a timescale of days to weeks.

PU Aurigae is an irregular variable star located in the constellation Auriga. A red giant, it varies by 0.1 magnitude around magnitude 5.64. Located around 560 light-years distant, it shines with a luminosity approximately 1,523 times that of the Sun and has a surface temperature of 3,482 K.

TW Andromedae (TW And) is an eclipsing binary star, classified also as an Algol variable star, in the constellation Andromeda. Its brightness varies with a period of 4.12 days, and has a typical brightness of magnitude 8.98 but decreasing down to a magnitude of 11.04 during the main eclipse.

It was given the variable star designation CU Chamaeleontis in 1981. Its spectrum is also variable. The spectral class is usually given as A0 or B9, sometimes with a giant luminosity class, sometimes main sequence. The spectrum shows strong variable emission lines indicative of a shell surrounding the star.

It has an integrated magnitude of 10.5 and is 1500 light- years from Earth. The variable star V380 Orionis is embedded in NGC 1999. Another famous nebula is IC 434, the Horsehead Nebula, near ζ Orionis. It contains a dark dust cloud whose shape gives the nebula its name.

Ptolemy, 350 years later, said it was as bright as Antares. The discrepancy may be due to Antares becoming brighter, but this is not known for certain. It could simply be caused by Beta Librae being a variable star, showing a present-day variability of 0.03 of a magnitude.

NGC 2439, with R Puppis the brightest star R Puppis (R Pup) is a variable star in the constellation Puppis. It is a rare yellow hypergiant and a candidate member of the open cluster NGC 2439. It is also an MK spectral standard for the class G2 0-Ia.

MWC 349 is a double (likely, triple) star system in the constellation Cygnus. Its properties are still debated and it may be a massive highly luminous star or a very young less luminous Herbig Ae/Be star. MWC 349 is also a variable star with the designation V1478 Cygni.

Y Lyncis is a semiregular variable star in the constellation Lynx. It is an asymptotic giant branch star of spectral type M6S, with a luminosity class of Ib, indicating a supergiant luminosity. It is around 800 light years away. Y Lyncis ranges in brightness from magnitude 6.8 to 8.9.

Many of the well-known bright stars are red giants, because they are luminous and moderately common. The red-giant branch variable star Gamma Crucis is the nearest M-class giant star at 88 light-years. The K0 red-giant branch star Arcturus is 36 light-years away.

T Microscopii is a semiregular variable star in the constellation Microscopium. It ranges from magnitude 6.74 to 8.11 over a period of 352 days. Located around 700 light-years distant, it shines with a bolometric luminosity 7,509 times that of the Sun and has a surface temperature of .

Z Chamaeleontis (abbreviated Z Cha) is a dwarf nova variable star system approximately 377 light-years away from the Sun, where two stars orbit each other every 1.78 hours. The system comprises an eclipsing white dwarf and red dwarf and possibly a yet unconfirmed third low-mass substellar companion.

Contrary to popular belief, Flamsteed did not assign the stars Flamsteed designations; rather, the French astronomer Joseph Jérôme de Lalande assigned Flamsteed numbers to stars in each constellation in order of right ascension. Since this star was the 68th star by right ascention in Cygnus, it was numbered 68 Cygni, the designation by which this star is most commonly known today, as most Latin-letter Bayer designations are no longer in common use. After the star was discovered to be variable, it was assigned a variable star designation. As the 1809th variable star without a Bayer designation to be discovered in Cygnus, 68 Cygni was assigned the designation V1809 Cygni in 1984.

15 Andromedae, abbreviated 15 And, is a single, variable star in the northern constellation of Andromeda. 15 Andromedae is the Flamsteed designation, while its variable star designation is V340 And. Its apparent visual magnitude is 5.55, which indicates it is faintly visible to the naked eye. Its estimated distance from the Earth is 252 light years, and it is moving further away with a heliocentric radial velocity of 13 km/s. Depending on the source, this star has been classified as a giant star with a stellar classification of A1 III, an A-type main-sequence star with a class of A1 Va, or a Lambda Boötis star with a class of kA1hA3mA0.5 Va+.

The brightness has been monitored by the American Association of Variable Star Observers since 1945, and it has been classified as an LC slow irregular variable star, whose apparent magnitude slowly varies between extremes of +0.6 and +1.6, although usually near magnitude +1.0. There is no obvious periodicity, but statistical analyses have suggested periods of 1,733 days or days. No separate long secondary period has been detected, although it has been suggested that primary periods longer than a thousand days are analogous to long secondary periods. Research published in 2018 demonstrated that Ngarrindjeri Aboriginal people from South Australia observed the variability of Antares and incorporated it into their oral traditions as Waiyungari (meaning 'red man').

The book received mixed reviews. SFF World felt it was written as though Heinlein himself were alive today, as it includes modern cultural references such as The Simpsons, but also noted some missteps, such as a section which reads, Sci-Fi Dimensions was more enthusiastic, saying, "Variable Star is both a worthy continuation of the Heinlein legacy and a darn fine Spider Robinson novel to boot." Variable Star by Spider Robinson and Robert A. Heinlein Nicholas Whyte of Strange Horizons says, "This is, frankly, not a great book." He criticizes the opening chapters, a sentiment expressed by other reviewers such as SFF World, calling them atrocious, and SF Reviews calling the plot twists contrived and absurd.

BZ Crucis is the bright star between the open clusters NGC 4609 and Hogg 15 HD 110432 is a Be star in the south-east of Crux, behind the center of the southern hemisphere's dark Coalsack Nebula. It has a stellar classification of B1IVe, which means it is a subgiant star of class B that displays emission lines in its spectrum. This is a variable star of the Gamma Cassiopeiae type, indicating it is a shell star with a circumstellar disk of gas about the equator, and has the variable star designation BZ Crucis. It is not known to be a member of a binary system, although it is probably a member of the open cluster NGC 4609.

It is a suspected variable star with a brightness that ranges from magnitude +4.77 to +4.86. This variation has pulsation periods of 23.4, 24.3, 27.9, and 34.1 days. The effective temperature of the stellar atmosphere is around 3,800 K, and it shines with 1,734 times the luminosity of the Sun.

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.

"The Crazy Years: Reflections of a Science Fiction Original". SF Site, 2005, review by Kit O'Connell In 2004, Robinson began working on a seven-page 1955 novel outline by the late Robert A. Heinlein to expand it into a novel. The book, titled Variable Star, was released on September 19, 2006.

The temperature minimum around 2.4 billion years goes along with a cosmic ray flux modulation by a variable star formation rate in the Milky Way. The reduced solar impact later results in a stronger impact of cosmic ray flux (CRF), which is hypothesized to lead to a relationship with climatological variations.

VX Sagittarii is a red supergiant or red hypergiant located more than 1.5 kiloparsec away from the Sun in the constellation of Sagittarius. It is a pulsating variable star with an unusually large magnitude range. It is also one of the largest stars discovered so far, with a radius varying between .

It has the variable star designation, RZ Arietis. It is generally considered to be an asymptotic giant branch star, having exhausted its core helium. Based on comparison of its current temperature and luminosity with theoretical evolutionary tracks, its initial mass is estimated to have been and its mass now is .

S Scuti is a carbon star located in the constellation Scutum. Parallax measurements by Hipparcos put it at a distance of approximately 1,300 light- years (390 parsecs). Its apparent magnitude is 6.80, making it visible to the naked eye only under excellent conditions. S Scuti is a semiregular variable star.

During an observation on March 25, 1917, 8 Flora was mistaken for the 15th-magnitude star TU Leonis, which led to that star's classification as a U Geminorum cataclysmic variable star. Flora had come to opposition on 1917 February 13, 40 days earlier. This mistake was uncovered only in 1995.

14 Aquarii (abbreviated 14 Aqr) is red giant star. 14 Aquarii is the Flamsteed designation; it also bears the variable star designation IW Aquarii. It is a semiregular variable with an amplitude of less than a tenth of a magnitude, and shows variations on a timescale of just one day.

QR Andromedae (often abbreviated to QR And) is an eclipsing binary star in the constellation Andromeda. Its maximum apparent visual magnitude is 12.16, but its light curve shows clearly eclipsing events where its brightness can drop to a magnitude of 13.07. This leads to its classification as an Algol variable star.

It is a suspected variable star of unknown type. Tau Cassiopeiae is 3.9 billion years old with about 1.44 times the mass of the Sun and 10 times the Sun's radius. It is radiating 40 times the Sun's luminosity from its expanded photosphere at an effective temperature of around 4,617 K.

WASP-33b is an extrasolar planet orbiting the star HD 15082. It is the first planet discovered to orbit a Delta Scuti variable star. With a semimajor axis of 0.026 AU and a mass which is likely greater than Jupiter mass, it belongs to the hot Jupiter class of planets.

Rotating ellipsoidal variables are a class of variable star. They are close binary systems whose components are ellipsoidal. They are not eclipsing, but fluctuations in apparent magnitude occur due to changes in the amount of light emitting area visible to the observer. Typical brightness fluctuations do not exceed 0.1 magnitudes.

Alpha Doradus is a blue-white star of magnitude 3.3, 176 light-years from Earth. It is the brightest star in Dorado. Beta Doradus is a notably bright Cepheid variable star. It is a yellow-tinged supergiant star that has a minimum magnitude of 4.1 and a maximum magnitude of 3.5.

HV 2112 was first reported as a variable star in 1908, by Henrietta Leavitt. At the time it was identified as Harvard no. 2112. No period was given, but it was reported to be "probably long". The magnitude range was given as 13.7 to fainter than 16.5, from photographic plates.

CQ Camelopardalis is a variable star in the constellation Camelopardalis. A red giant of spectral type M0II, it varies irregularly from magnitude 5.15 to 5.27. Located around 650 parsecs distant, it shines with a luminosity over 20,000 times that of the Sun and has a surface temperature of 3,790 K.

HD 100307 is a suspected variable star in the constellation of Hydra. Its apparent magnitude is 6.16, but interstellar dust makes it appear 0.346 magnitudes dimmer than it should be. It is located some 340 light-years (104 parsecs) away, based on parallax. HD 100307 is a M-type red giant.

Beta Cassiopeiae (β Cassiopeiae, abbreviated Beta Cas or β Cas), officially named Caph , is a Delta Scuti variable star in the constellation of Cassiopeia. It is a giant star belonging to the spectral class F2. The white star of second magnitude (+2.27 mag) has an absolute magnitude of +1.16 mag.

This is a variable star most likely of the RS CVn type with an amplitude of 0.15 in magnitude, and it displays magnetic activity. It has 5.25 times the mass of the Sun and, having exhausted the supply of hydrogen at its core, has expanded to 38 times the Sun's radius.

Shortly before he retired, he succeeded in detecting technetium in the variable star R Andromedae and other red variables. Since technetium has no stable isotopes, it must have been produced recently in any star in which it is found, and this is direct evidence of the s-process of nucleosynthesis.

This is a variable star tentatively classified as a slow irregular type variable with a brightness that varies between magnitude +4.89 and +4.94. With around 56 times the Sun's radius, it shines with a luminosity approximately 2,973 times that of the Sun and has a surface temperature of 4,030 K.

U Microscopii is a Mira variable star in the constellation Microscopium. It ranges from magnitude 7 to 14.4 over a period of 334 days. The Astronomical Society of Southern Africa in 2003 reported that observations of U Microscopii were very urgently needed as data on its light curve was incomplete.

BL Boötis type stars are a subtype of RR Lyrae variables. T Boötis was a nova observed in April 1860 at a magnitude of 9.7. It has never been observed since, but that does not preclude the possibility of it being a highly irregular variable star or a recurrent nova.

Its variable star designation is IL Aquarii and it is classified as a BY Draconis variable. Its brightness fluctuates by around 0.04 magnitudes. This type of variability is thought to be caused by large starspots moving in and out of view as the star rotates. Gliese 876 emits X-rays.

He was able to devote considerable time in the observation of comets and variable stars. He discovered several comets and investigated the cause of the brightness change of the variable star Mira. He is credited with being the first to observe the Nova 1670 Vulpeculae, the first ordinary nova discovered in modern times.

The same photometry found a possible period of but this was very uncertain and no variability type could be determined. It is listed in the General Catalogue of Variable Stars as a possible slow irregular variable. It was classified as a variable star in 1977, on the basis of a 1960 study.

The daughter of Phorcys and Ceto, Stheno was born in the caverns beneath Mount Olympus. She and her sister Euryale were both immortal, and the third sister, Medusa, was mortal.Wilk, Stephen R. "Mythological Evidence for Ancient Observations of Variable Stars." Journal of the American Association of Variable Star Observers 24 (1996): 129-133.

38 Arietis (abbreviated 38 Ari) is a variable star in the northern constellation of Aries. 38 Arietis is the Flamsteed designation. It was once designated 88 Ceti, forming part of the neighboring constellation of Cetus. With an apparent visual magnitude of +5.18, it is bright enough to be viewed with the naked eye.

Phi Draconis (φ Dra / φ Draconis) is a fourth-magnitude variable star in the constellation Draco. It has the Flamsteed designation 43 Draconis. It is also a triple star system where the brightest component is a chemically peculiar Ap star. The brightness of φ Draconis varies by about 0.04 magnitudes every 1.7 days.

T Antliae (also abbreviated T Ant) is a Classical Cepheid variable star that is between 10 and 12,000 light-years away from the Sun in the constellation of Antlia. A yellow-white supergiant with a spectral type of F6Iab, it ranges between apparent magnitude 8.86 and 9.76 over a period of 5.89820 days.

TT Corvi (TT Crv) is a semiregular variable star in the constellation Corvus. It is a red giant of spectral type M3III and average apparent magnitude 6.48 around 923 light years distant. It shines with a luminosity approximately 993 times that of the Sun and has a surface temperature of 3630 K.

Describes double stars, variable star, star clusters, nebulas, globular clusters, and galaxies. Explains how astronomers determine the distances to stars and galaxies, how sky objects are designated, and how to use deep-sky charts. Includes an atlas of 20 star charts. The charts are ideal for stargazers using a small telescope or binoculars.

DP Leonis (abbreviated DP Leo) is an eclipsing binary system approximately 1304 light-years away from the Sun, probably a cataclysmic variable star of the AM Herculis-type also known as polars. The system comprises an eclipsing white dwarf and red dwarf in tight orbit (nearly 1.5 hours) and an extrasolar planet.

RX Telescopii is an irregular variable star in the constellation Telescopium. It has a maximum magnitude of 6.45 and a minimum magnitude 7.47. It is a red supergiant with a spectral type of M3Iab. If placed in our solar system, it's photosphere would engulf the orbit of Jupiter, nearing that of Saturn.

The angle between the two components is 1°. Mesarthim was discovered to be a double star by Robert Hooke in 1664, one of the earliest such telescopic discoveries. The primary, γ1 Arietis, is an Alpha² Canum Venaticorum variable star that has a range of 0.02 magnitudes and a period of 2.607 days.

Gamma Doradus (Gamma Dor, γ Doradus, γ Dor) is the third-brightest star in the constellation of Dorado.Gamma Dor , Jim Kaler, Stars. Accessed on line November 17, 2008. It has an apparent visual magnitude of approximately 4.25 and is a variable star, the type star of the class of Gamma Doradus variables.

AD Andromedae (AD And) is an eclipsing binary in the constellation Andromeda. Its maximum apparent visual magnitude is 11.2, but it shows a decrease of 0.62 magnitudes during the main eclipse and 0.58 during the secondary one. It is classified as a Beta Lyrae variable star with a period of almost one day.

Observations of its atmosphere suggest that it is losing mass at a rate of per year. RW Cygni is classified as a semiregular variable star. It is given the subtype SRc, indicating that it is a cool supergiant. Its brightness varies from extremes of magnitude +8.0 and +9.5 with a period of .

It is radiating 89 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,400 K. Kappa Leonis has a magnitude 10.4 companion at an angular separation of 2.1 arc seconds. The pair most likely form a binary star system. The companion is a suspected variable star.

It could be quite old, perhaps in excess of 10 Gyr. It is a pulsating variable star of the V361 Hydrae type (or also called sdBVr type). It is believed that the star's mass when it was still on the main sequence was between 0.8 and 0.9 times that of the Sun.

He was followed by Herbert C. Wilson, who served in the post between 1909 and 1926. The magazine played an important role in the development of amateur variable star observing in the United States. In 2017 Popular Astronomy has returned as part of TechnicaCuriosa.com, along with sister titles Popular Electronics and Mechanix Illustrated.

The sun-like star 61 Virginis has three planets: one is a super-Earth and two are Neptune-mass planets. SS Virginis is a variable star with a noticeable red color. It varies in magnitude from a minimum of 9.6 to a maximum of 6.0 over a period of approximately one year.

Luyten 726-8, also known as Gliese 65, is a binary star system that is one of Earth's nearest neighbors, at about 8.7 light years from Earth in the constellation Cetus. Luyten 726-8B is also known under the variable star designation UV Ceti, being the archetype for the class of flare stars.

In the early 19th century few variable stars were known, so it seemed reasonable to use the letters of the Latin script. Because very few constellations contained stars with uppercase Latin-letter Bayer designation greater than Q, the letter R was chosen as a starting point so as to avoid confusion with letter spectral types or the (now rarely used) Latin-letter Bayer designations. Although Lacaille had used uppercase R to Z letters in a few cases, for example X Puppis (HR 2548), these designations were either dropped or accepted as variable star designations. The star T Puppis was accepted by Argelander as a variable star and is included in the General Catalogue of Variable Stars with that designation but is now classed as non-variable.

Despite its youth, it shows an enhancement of Alpha process elements. Possibly this is due to an enhancement of its birth molecular cloud by a nearby Type II supernova explosion. At least nine variable star members have been identified with high probability, plus 29 lower probability members. The former include two eclipsing binary star systems.

W Sagittarii (W Sgr, Gamma-1 Sagittarii (γ¹ Sgr)) is a multiple star system star in the constellation Sagittarius, and a Cepheid variable star. W Sagittarii is an optical line-of-sight companion nearly a degree from the much brighter γ2 Sgr (Al Nasl) which marks the nozzle or spout of the teapot asterism.

Omicron¹ Eridani (ο¹ Eridani, abbreviated Omicron¹ Eri, ο¹ Eri), also named Beid , is a variable star in the constellation of Eridanus. With an average apparent visual magnitude of 4.04, it is visible to the naked eye on a clear, dark night. Based upon parallax measurements, it lies approximately 122 light- years from the Sun.

Rho2 Arietis is an M-type red giant star in the northern constellation of Aries. With an annual parallax shift of 9.28 mas, it is approximately distant from the Earth. Rho2 Arietis is classified as a semiregular variable star with periods of 49.9 and 54.8 days. It varies in visual magnitude between 5.45 and 6.01.

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.

Further observations suggested a possible rotation period of around 42 days. Samus et al. (2017) classify it as a suspected RS Canum Venaticorum variable, meaning that it is a close binary star whose components have star-spots that cause rotationally-modulated variations in brightness. It has been given the variable star designation V2008 Cygni.

LL Pegasi (AFGL 3068) is a Mira variable star surrounded by a pinwheel-shaped nebula, IRAS 23166+1655, thought to be a preplanetary nebula. It is a binary system that includes an extreme carbon star. The pair is hidden by the dust cloud ejected from the carbon star and is only visible in infrared light.

There are several variable stars in Lepus. R Leporis is a Mira variable star. It is also called "Hind's Crimson Star" for its striking red color and because it was named for John Russell Hind. It varies in magnitude from a minimum of 9.8 to a maximum of 7.3, with a period of 420 days.

Zeta Cassiopeiae (ζ Cassiopeiae, abbreviated Zet Cas, ζ Cas), officially named Fulu , is a variable star in the constellation of Cassiopeia. It has a blue- white hue and is classified as a B-type subgiant with an apparent magnitude of +3.66. Based upon parallax measurements, it is approximately 590 light-years from the Sun.

AH Scorpii is a dust-enshrouded red supergiant and is classified as a semiregular variable star with a main period of 714 days. The total visual magnitude range is 6.5 - 9.6. No long secondary periods have been detected. Modelling of AH Scorpii near maximum light has determined an effective temperature of and a luminosity of .

William Tyler Olcott (1873-1936) was an American lawyer and amateur astronomer. In 1909, after attending a lecture by Edward Charles Pickering, he developed an interest in observing variable stars. In 1911, he founded the American Association of Variable Star Observers (AAVSO). W. Olcott also published several books to popularize the field of amateur astronomy.

The estimated distance of the Andromeda Galaxy from our own was doubled in 1953 when it was discovered that there is another, dimmer type of Cepheid variable star. In the 1990s, measurements of both standard red giants as well as red clump stars from the Hipparcos satellite measurements were used to calibrate the Cepheid distances.

V433 Aurigae is a variable star in the constellation Auriga. It is a Slowly pulsating B star (SPB) that ranges from apparent magnitude 6.02 to 6.06 over 4.6 days. Located around 324 parsecs distant, it shines with a luminosity approximately 322 times that of the Sun and has a surface temperature of 7400 K.

A slow irregular variable (ascribed the GCVS types L, LB and LC) is a variable star that exhibit no or very poorly defined periodicity in their slowly changing light emissions. These stars have often been little-studied, and once more is learnt about them, they are reclassified into other categories such as semiregular variables.

8900 AAVSO, provisional designation ', is a stony background asteroid from the central region of the asteroid belt, approximately 5.5 kilometers in diameter. It was discovered by American amateur astronomer Dennis di Cicco at the U.S Sudbury Observatory , Massachusetts, on 24 October 1995. The asteroid was named after the American Association of Variable Star Observers (AAVSO).

AZ Phoenicis (HR 239) is a variable star in the constellation of Phoenix. It has an average visual apparent magnitude of 6.47, so it is at the limit of naked eye visibility. From parallax measurements by the Gaia spacecraft, it is located at a distance of from Earth. Its absolute magnitude is calculated at 1.65.

Kappa Herculis A is a giant star with stellar classification G8III. With a mass of and radius that is , the star boasts a bolometric luminosity that is . Its slightly companion is cooler and about a third of the luminosity. Kappa Herculis is a suspected variable star with a reported magnitude range of 4.70 to 5.02.

36 examples of an unusual type of variable star were discovered in the cluster. These fast-rotating pulsating B-type stars vary by only a few hundredths of a magnitude with periods less than half a day. They are main sequence stars, hotter than δ Scuti variables and cooler than slowly pulsating B stars.

Coronal stars are ubiquitous among the stars in the cool half of the Hertzsprung–Russell diagram. These coronae can be detected using X-ray telescopes. Some stellar coronae, particularly in young stars, are much more luminous than the Sun's. For example, FK Comae Berenices is the prototype for the FK Com class of variable star.

HD 211392 is a suspected variable star in the equatorial constellation of Aquarius, positioned about 370 light-years away. With an apparent magnitude close to six, according to the Bortle scale it is just visible to the naked eye from dark, rural skies. It is a giant star with a stellar classification of K3III.

Margaret Walton Mayall (January 27, 1902 – December 6, 1995) was an American astronomer. She was the director of the American Association of Variable Star Observers (AAVSO) from 1949 to 1973. Mayall (born Margaret Lyle Walton) was born in Iron Hill, Maryland, on 27 January 1902. She attended the University of Delaware and Swarthmore College.

HD 105382 (also known as V863 Centauri) is a star in the constellation Centaurus. Its apparent magnitude is 4.47. From parallax measurements, it is located 130 parsecs (440 light years) from the sun. HD 105382 is a variable star whose apparent magnitude varies with an amplitude of 0.012 over a period of 1.295 days.

The most massive and luminous component of the pair has the variable star designation GX Andromedae. It is a main sequence red dwarf star of spectral type M1.4 that varies his brightness due to stellar flares. Gaia observations suggest a rotation period of 44 days and a magnetic activity cycle of roughly 9 years.

In 1888 he married Anna Greenleaf. He returned to Marengo, Illinois where he kept a small, private observatory that he used primarily for variable star observation. The Yerkes Observatory was built nearby in 1897, and in 1898 he joined the staff as a volunteer research assistant. By 1900 he was appointed as an assistant.

The star appears to be a Beta Cephei variable with a pulsation period of 0.0919 days and an amplitude of 0.0080 in magnitude. The magnitude 5.39 secondary, component B, is classified as a Gamma Cassiopeiae type variable star. Due to its variable nature, the brightness of the system varies from magnitude +4.42 to +4.82.

Kappa Trianguli Australis (κ Trianguli Australis) is a star in the constellation Triangulum Australe. Kappa Trianguli Australis is a yellow G-type supergiant with an apparent magnitude of +5.08. It is around 1,200 light years from Earth. It is not generally listed as a variable star but Hipparcos photometry showed small amplitude brightness changes.

T Normae is a Mira variable star. It is located midway between Eta Normae and Gamma Circini. It ranges from magnitude 6.2 to 13.6 and a period of 244 days. Located around 900 light-years distant, it shines with a luminosity 760 times that of the Sun and has a surface temperature of 3234 K.

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.

He worked with Freeman Dyson on Project Orion, the design of a spacecraft propelled by atomic bombs. RS Puppis, a Cepheid variable star. Christy explained why they pulsate. During a sabbatical year at Princeton University in 1960, Christy began an investigation of Cepheid variables and the smaller RR Lyrae variables, classes of luminous variable stars.

An Orion variable is a variable star which exhibits irregular and eruptive variations in its luminosity and is typically associated with diffuse nebulae. It is thought that these are young stars which will later become regular, non- variable stars on the zero-age main sequence. Brightness fluctuations can be as much as several magnitudes.

Mu Sagittarii A varies in brightness and is classified as a variable star. The two spectroscopic components eclipse each other with an orbital period of 181 days, causing a 0.08 magnitude drop in brightness (from +3.84 to +3.96). In addition, it shows more irregular variations typical of an Alpha Cygni variable, irregularly pulsating hot supergiant stars.

This is the list of 16 extrasolar planets that were detected by timing –– 5 by pulsar timing and 11 by variable star timing, sorted by orbital periods. It works by detecting the changes in radio emissions from pulsars caused by the gravity of orbiting planets. Same thing works for variable stars, not by radio but light.

The detected pulsation modes correspond to those for both and β Cephei variables and slowly pulsating B stars. Similar pulsations have not been detected in component Ab, but it is possible that it is also a variable star. Aa is 12.02 ± 0.13 times as massive as the Sun, while Ab is 10.58 ± 0.18 times as massive.

T Ceti is a semiregular variable star located in the equatorial constellation of Cetus. It varies between magnitudes 5.0 and 6.9 over 159.3 days. The stellar parallax shift measured by Hipparcos is , which yields a distance estimate of roughly 900 light years. It is moving further from the Earth with a heliocentric radial velocity of +29 km/s.

XX Persei is a semiregular variable star of sub-type SRc, indicating a cool supergiant. The General Catalogue of Variable Stars gives the period as 415 days. It also shows a long secondary period which was originally given at 4,100 days. A more recent study shows only slow variations with a period of 3,150 ± 1,000 days.

S Pegasi (S Peg) is a Mira variable star in the constellation Pegasus. It varies between magnitude 7 and 13 with a period of 319.22 days. It is believed to be pulsating in the first overtone. First overtone pulsators have masses less than at a temperature of 2,107 K, and less than at the luminosity of S Pegasi.

30 Piscium (HIP 154) is a solitary variable star in the zodiac constellation of Pisces. It is visible to the naked eye with an apparent visual magnitude of 4.37. The distance to this star, based upon an annual parallax shift of , is around 410 light years. It is moving closer with a heliocentric radial velocity of −12 km/s.

For many years, Phoebe was an observer, volunteer and benefactor of the American Association of Variable Star Observers (AAVSO). The AAVSO, founded in 1911, was an organization which fostered collaboration between citizen scientists and professionals. John Crane willed his 4-inch Clark refractor to the AAVSO. After he died in 1927, Phoebe Waterman Haas was able to obtain it.

It is a suspected variable star, with an amplitude of 0.012 magnitude and period 4.4 days. The star has 1.3 times the mass of the Sun and has expanded to nearly 52 times the Sun's radius. It is radiating 551 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,000 K.

Helen Lines (died 2001) was an American amateur astronomer. In her beginnings she was a deep-sky observer and astrophotographer. She was one of early members of the Phoenix Astronomical Society and a member of the American Association of Variable Star Observers. She and her husband Richard D. Lines built a small observatory in Mayer, Arizona.

Y Sagittarii is a variable star in the constellation of Sagittarius. It is a Cepheid variable in apparent magnitude +5.77. This star is the third-brightest in this constellation after X Sagittarii and W Sagittarii. The measure of its parallax by Hubble Space Telescope puts Y Sagittarii to 1,293 light-years away from the Solar System.

L 1159-16 is a variable star. It is a flare star, showing brief increases in brightness due to eruptions from its surface. In the ultraviolet, flares of over a magnitude have been observed. In addition it shows longterm variations in brightness which may be due to starspots and rotation, possibly classifying it as a BY Draconis variable.

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.

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.

Gamma Boötis (γ Boötis, abbreviated Gamma Boo, γ Boo) is a binary star in the constellation of Boötes. It is a Delta Scuti type variable star with a period of 1.13 hours. Its brightness varies from magnitude +3.02 to +3.07. Based on parallax measurements obtained during the Hipparcos mission, it is approximately 85 light-years distant from the Sun.

This is a giant star with a stellar classification of K4 III. It is a suspected variable star that apparently ranges in magnitude between 4.35 and 4.45. The measured angular diameter of this star is . At the estimated distance of Delta Ophiuchi, this yields a physical size of about 33 times the radius of the Sun.

Over the years there have been various activities related to astronomy: observation of sunspots, variable star observing, astrophotography, supernova search, observation of comets, occultations, teaching courses, the public open days, etc. Undoubtedly the main activity of the Observatory San Jose, faithful to the purpose for which it was founded, is the teaching and dissemination of astronomy.

UY Scuti is a red supergiant pulsating variable star and is also one of the largest stars currently known with a radius of 1,708 times that of the Sun. Stephenson 2-18 is another red supergiant star and is frequently described as the largest star currently known, with a radius of 2,150 times that of the Sun.

DI Chamaeleontis, also known as Hen 3-593 or HIP 54365, is a quadruple star system in the constellation Chamaeleon. The system is roughly 700 light years from Earth. DI Cha is a variable star of the T Tauri type, young stellar objects just approaching the main sequence. It varies erratically between visual magnitudes 10.65 and 10.74.

AW Canum Venaticorum is a variable star in the constellation Canes Venatici. It is visible to the naked eye with a nominal apparent visual magnitude of 4.76. The distance to this star, as measured from its annual parallax shift of , is around 620 light years. It is moving closer with a heliocentric radial velocity of −44 km/s.

HD 88366 (S Carinae) is a star in the constellation Carina. HD 88366 is an M-type red giant with a mean apparent magnitude of +6.94. It is approximately 1,620 light years from Earth. It is classified as a Mira type variable star and its brightness varies between magnitude +4.5 and +10.0 with a period of 149.49 days.

At an age of around four billion years, it has expanded to 12 times the radius of the Sun and shines with 60 times the Sun's luminosity. The effective temperature of the star's outer atmosphere is 4,688. In the General Catalogue of Variable Stars, it is listed as a suspected variable star with a maximum magnitude of 4.97.

V343 Carinae is a blue-white star or star system in the southern constellation of Carina. It has the Bayer designation d Carinae, while V343 Carinae is a variable star designation. The star is visible to the naked eye with an apparent visual magnitude of 4.31. The distance to this object is approximately 1,440 light years based on parallax.

NO Aurigae is listed in the General Catalogue of Variable Stars as a slow irregular variable, indicating that no regularity could be found in the brightness variations. Other studies have suggested possible periods of 102.1, 173, and 226 days, and would classify it as a semiregular variable star. The maximum visual magnitude range is 6.05–6.50.

The interferometry- measured angular diameter of this star is , which, at its estimated distance, equates to a physical radius of about 137 times the radius of the Sun. It is classified as a semi-regular variable star and its brightness varies by an amplitude of 0.0636 in magnitude. The identified pulsation periods are 32.3, 38.5, and 44.9 days.

Félix de Roy (25 July 1883 – 15 May 1942) was a Belgian astronomer, born in Antwerp. He observed and recorded more than 5,000 variable stars during his career. He was a member of the British Astronomical Association and directed its Variable Star Section between 1922 and 1939. He also occasionally observed meteors for the British Astronomical Association.

V428 Andromedae is the variable star designation for HD 3346. It is a short-period semi-regular variable (type SRS), also called an ultra- small-amplitude pulsating red giant. It has an amplitude of only 0.065 magnitudes. The main pulsation period is 11.5 days, but other periods of 11, 15, and 22 days have been detected.

It has a minimum magnitude of 10 and a period of 390 days. V Hydrae is an unusually vivid red variable star 20,000 light-years from Earth. It varies in magnitude from a minimum of 9.0 to a maximum of 6.6. Along with its notable color, V Hydrae is also home to at least two exoplanets.

DY Persei is a variable star and carbon star in the Perseus constellation. At maximum it is 11th magnitude carbon star and at its faintest it drops to 16th magnitude. DY Persei the prototype of the very rare DY Persei class of variables, that pulsate like red variables but also fade from sight like R Coronae Borealis variables.

Dutch mathematician F. J. M. Barning analyzed the resulting data in 1963 and found four separate cycles of variation. By 1994, six periods had been confirmed. The variable star designation of the primary is DD Lacertae, while 12 Lacertae is the Flamsteed designation. In general terms it varies in magnitude from 5.16 down to 5.28 with a period of .

Although most barium stars are in binary systems, η Eridani has no known companion. η Eridani is a high proper motion star, a relatively close star that is moving across the sky at a high rate compared to most stars. It is suspected to be a variable star with a range from magnitude 3.81 to 3.90.

Artist's illustration of plasma ejections from V Hydrae. V Hydrae is a semiregular variable star of type SRa, sometimes considered to be a Mira variable. It pulsates with a period of 530 days and a brightness range of 1-2 magnitudes, but also shows deep fades at intervals of about 6,160 days when it may drop below magnitude 12.

It is still expanding and may become a red supergiant, or perhaps has already passed that phase, but in either case it will become a supernova within the next few million years. Aludra is classified as an Alpha Cygni type variable star and its brightness varies from magnitude +2.38 to +2.48 over a period of 4.7 days.

RU Camelopardalis in optical light RU Camelopardalis is both a Carbon star and a type II Cepheid variable star. This is unusual but not unique. At least five other relatively bright examples are known, two of which are of the BL Herculis sub-type. The atmosphere contains more carbon than oxygen but is not deficient in hydrogen.

S Normae is the brightest member of the open cluster NGC 6087. S Normae (S Nor) is a yellow supergiant variable star in the constellation Norma. It is the brightest member of the open cluster NGC 6087. S Normae is a Classical Cepheid variable with a visual magnitude range of 6.12 to 6.77 and a period of 9.75411 days.

RZ Normae is an R Coronae Borealis type variable star in the constellation Norma. It has a baseline magnitude of 10.2, dropping down to dimmer than 16.2 at its minima. It was discovered by the astronomer Sergei Gaposchkin in 1952. It has around 60% the mass of the Sun and an effective (surface) temperature of around 6750 K.

In the northwest part of Taurus is the supernova remnant Messier 1, more commonly known as the Crab Nebula. One of the closest regions of active star formation, the Taurus-Auriga complex, crosses into the northern part of the constellation. The variable star T Tauri is the prototype of a class of pre-main-sequence stars.

Grey talks about his personal philosophy in the 2009 film Cognition Factor. In Variable Star, a 2006 science fiction novel written by Spider Robinson based on a story outline by Robert A. Heinlein, Robinson devotes several pages to his protagonist's discovery of Grey's Sacred Mirrors and Progress of the Soul series, and to using them to enhance meditation.

RR Centauri is a variable star of apparent magnitude maximum +7.29. It is located in the constellation of Centaurus, approximately 320 light years distant from the solar system. The system is a contact binary of the W UMa type - two stars in physical contact whose two components share a gaseous envelope. Its spectral type is A9V or F0V.

Xi1 Canis Majoris, Latinized from ξ1 Canis Majoris, is a Beta Cephei variable star in the constellation Canis Major. It is approximately 1,400 light years from Earth. ξ1 Canis Majoris is a blue-white B-type star. It has generally been assigned a luminosity class of III (giant) or IV (subgiant), for example B1III or B0.5IV.

An Alpha2 Canum Venaticorum variable (or α2 CVn variable) is a type of variable star. These stars are chemically peculiar main sequence stars of spectral class B8p to A7p. They have strong magnetic fields and strong silicon, strontium, or chromium spectral lines. Their brightness typically varies by 0.01 to 0.1 magnitudes over the course of 0.5 to 160 days.

Mu Cephei is a variable star and the prototype of the obsolete class of the Mu Cephei variables. It is now considered to be a semiregular variable of type SRc. Its apparent brightness varies erratically between magnitude 3.4 and 5.1. Many different periods have been reported, but they are consistently near 860 days or 4,400 days.

KY Cyg lies near the bright open cluster NGC 6913, but is not thought to be a member. The location is close to the bright star γ Cygni. It was identified as a variable star in 1930, and later named as KY Cygni. The spectrum was given the MK classification of M3 Ia, with only minor adjustments since.

This is possibly a type of variable star known as a slowly pulsating B-type star. It has a longitudinal magnetic field with a mean strength of . A projected stellar rotation velocity of about 14 km s−1 is considered low for a star of this type, which may indicate it is being viewed from nearly pole-on.

HR 2554 has two components in orbit around each other, making it a binary star. The semi-major axis of the secondary's orbit is 2.17 arcseconds. The two components regularly eclipse each other, making A Carinae a variable star. Its brightness varies by 0.06 magnitudes with a period equal to its orbital period of 195 days.

DU Lyncis is a single variable star in the constellation Lynx. It is a faint star but visible to the naked eye with an apparent visual magnitude of 5.15. With an annual parallax shift of , it is located some 350 light years from the Sun. The star is moving closer with a heliocentric radial velocity of −37 km/s.

AK Pyxidis is a semiregular variable star located in the constellation Pyxis. It varies between magnitudes 6.09 and 6.51, pulsating to multiple periods simultaneously of 55.5, 57.9, 86.7, 162.9 and 232.6 days. Located around 1228 light-years distant, it shines with a luminosity approximately 1500 times that of the Sun and has a surface temperature of 3410 K.

UZ Pyxidis (HD 75021) is a semiregular variable star in the constellation Pyxis. It is located about 6,000 light-years (2,000 parsecs) away from the Earth. UZ Pyxidis lies directly between α and γ Pyxidis. It has a common proper motion companion, HD 75022, less than 2' away but the two are not listed in double star catalogues.

It is also unusual in that it has very strong isotopic bands of C2 and CN. UZ Pyxidis is classified as a semiregular variable with a dominant period of 159.6 days. It varies in brightness between magnitude 6.99 and 7.63. The variability was first reported in 1972, and the variable star designation UZ Pyxidis was assigned in 1978.

V385 Andromedae is a variable star in the constellation Andromeda, about away. It is a red giant over a hundred times larger than the sun. It has an apparent magnitude around 6.4, just about visible to the naked eye in ideal conditions. V385 Andromedae was identified as a long-period variable in 1999 from analysis of Hipparcos photometry.

U Orionis lies less than half a degree east of the small-amplitude variable star χ1 Orionis and less than an arc-minute from the much fainter eclipsing variable UW Orionis. χ1 Orionis is slightly brighter than U Orionis at its brightest maximum, while UW Orionis is more than a thousand times fainter, similar to U Orionis at minimum.

The constellation's two brightest stars—Alpha and Epsilon Antliae—shine with a reddish tinge. Alpha is an orange giant of spectral type K4III that is a suspected variable star, ranging between apparent magnitudes 4.22 and 4.29. It is located 320 ± 10 light-years away from Earth. Estimated to be shining with around 480 to 555 times the luminosity of the Sun, it is most likely an ageing star that is brightening and on its way to becoming a Mira variable star, having converted all its core fuel into carbon. Located 590 ± 30 light-years from Earth, Epsilon Antliae is an evolved orange giant star of spectral type K3 IIIa, that has swollen to have a diameter about 69 times that of the Sun, and a luminosity of around 1279 Suns.

Most Mira variables do exhibit slight cycle-to- cycle changes in period, probably caused by nonlinear behaviour in the stellar envelope including deviations from spherical symmetry. Mira variables are popular targets for amateur astronomers interested in variable star observations, because of their dramatic changes in brightness. Some Mira variables (including Mira itself) have reliable observations stretching back well over a century.

HD 74180 is a binary star in the constellation Vela. It is approximately 3,200 light years from Earth. The primary component is a yellow-white F-type supergiant with a mean apparent magnitude of +3.81, with a 10th magnitude companion 37.5 arcseconds distant. b Velorum has been classified as a suspected α Cygni variable star which varies by only 0.06 magnitude.

P Cygni (34 Cyg) is a variable star in the constellation Cygnus. The designation "P" was originally assigned by Johann Bayer in Uranometria as a nova. Located about 5,000 to 6,000 light-years (1,500–1,800 parsecs) from Earth, it is a hypergiant luminous blue variable (LBV) star of spectral type B1Ia+ that is one of the most luminous stars in the Milky Way.

It figures close to the hyponeuse of the right-angled triangle of Alpha, Beta and Delta, the three brightest stars of Indus. T Indi is the only bright variable star in Indus. It is a semi-regular, deeply coloured red giant with a period of 11 months, 1900 light-years away. Its minimum magnitude is 7 and its maximum: 5.

Sirius was the basis for the ancient Egyptian calendar. The star marked the Great Dog's mouth on Bayer's star atlas. Flanking Sirius are Beta and Gamma Canis Majoris. Also called Mirzam or Murzim, Beta is a blue-white Beta Cephei variable star of magnitude 2.0, which varies by a few hundredths of a magnitude over a period of six hours.

Omicron1 Centauri (ο1 Cen, ο1 Centauri) is a star in the constellation Centaurus. It is approximately 6,000 light years from Earth. ο1 Centauri is a yellow G-type supergiant or hypergiant with a mean apparent magnitude of +5.13. It is classified as a semiregular variable star and its brightness varies from magnitude +5.8 to +6.6 with a period of 200 days.

Omicron2 Centauri (ο2 Cen, ο2 Centauri) is a star in the constellation Centaurus. ο2 Centauri is a white A-type supergiant with a mean apparent magnitude of +5.12. It is approximately 5000 light years from Earth. It is classified as an Alpha Cygni type variable star and its brightness varies from magnitude +5.12 to +5.22 with a period of 46.3 days.

She reported her observations of variable stars to the American Association of Variable Star Observers (AAVSO), submitting 338 observations from 1928 to 1933. She also taught her children and friends about astronomy. In 1953, the AAVSO separated from Harvard College Observatory, losing both its physical location and much of its funding. Phoebe Waterman Haas volunteered to assist the AAVSO Director, Margaret Mayall.

1 Camelopardalis B is 10" away and is probably an early B class subgiant. There is an 11th magnitude star 150" away. It is unclear whether it is a member of a triple system, or if the fainter star is only a foreground object lying in the same direction. 1 Camelopardalis A is a variable star with a small amplitude.

15 Camelopardalis is a triple star system in the northern circumpolar constellation of Camelopardalis. It has the variable star designation DV Camelopardalis; 15 Camelopardalis is the Flamsteed designation. This is just visible to the naked eye as a dim, blue-white hued star with a baseline apparent visual magnitude of 6.13. It is a probable (99%) member of the Cas- Tau OB association.

The brightest stars of the cluster are of 11th magnitude and the brightest main sequence stars are of late B of A type. Two blue stragglers have been detected in the cluster, one variable star and eleven red giants. The turn-off mass of the cluster is estimated to be at 3.1 . The cluster has the same metallicity as the Sun.

V528 Carinae (V528 Car, HD 95950, HIP 54021) is a variable star in the constellation Carina. V528 Carinae has an apparent visual magnitude of +6.75. It is a distant star but the exact distance is uncertain. The Hipparcos satellite gives a negative annual parallax and is not helpful, while the Gaia Data Release 2 parallax of implies a distance around .

This minor planet was named in honour of American astronomer and gay rights activist Frank Kameny (1925–2011), by the Minor Planet Center and the International Astronomical Union on 3 July 2012. Frank Kameny was a Harvard-trained variable star astronomer. He died 11 October 2011. The approved naming citation was published by the Minor Planet Center on 3 July 2012 ().

OGLE-LMC-CEP0227 is an eclipsing binary (Cepheid variable) star, pulsating every 3.8 days. The star, in the Large Magellanic Cloud, was the first Cepheid star system found to be orbiting exactly edge on. The binary stars orbit each other 'edge on' to the line of sight from the earth. This unique configuration has allowed astronomers to refine their understanding of Cepheid stars.

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.

Finally, the 'p' shows some peculiarity in the spectrum. It is classified as a Gamma Cassiopeiae type variable star and its brightness varies from magnitude +5.43 to +5.61. This is a runaway star with a peculiar velocity of . Because it is a binary star system, it was most likely not turned into a runaway system as the result of a supernova explosion.

The two stars orbit every five years and their separation varies from five to seven astronomical units in a mildly eccentric orbit. u Aql A is a classical Cepheid variable star ranging between magnitudes 6.08 and 6.86 over a period of 7.02 days. It is an evolved star which has exhausted its core hydrogen and is now fusing helium into carbon.

The galaxy was identified as a blue compact dwarf, a type of small irregular galaxy undergoing a strong burst of star formation. The spectrum of PHL 293B is unusual both for its low metallicity and for broad hydrogen emission lines with P Cygni profiles. The emission lines are interpreted as being from a single luminous blue variable star within the galaxy.

R Trianguli Australis is a yellow-white hued variable star in the southern constellation Triangulum Australe. It is near the limit of visibility to the naked eye, having a typical apparent visual magnitude of 6.73. Based upon an annual parallax shift of , it is located 2,210 light years away. R TrA is moving closer with a heliocentric radial velocity of −13 km/s.

18 Aquilae (abbreviated 18 Aql) is a triple star system in the constellation of Aquila. 18 Aquilae is the Flamsteed designation; it also bears the variable star designation Y Aquilae. It has an apparent visual magnitude of 5.07. The distance to this system can be estimated from the annual parallax shift of 6.43 mas, yielding a value of around away from Earth.

T Pyxidis (T Pyx)According to the Argelander system of nomenclature for variable stars, the initial letter is an R, and the counter progresses alphabetically. Thus, T Pyx is the third variable star in the constellation Pyx. is a recurrent nova and nova remnant in the constellation Pyxis. It is a binary star system and its distance is estimated at about from Earth.

The distance to this system, based upon an annual parallax shift of , is around 660 light years. It is moving closer to the Earth with a heliocentric radial velocity of −32 km/s. The primary component is an aging giant star with a stellar classification of K4 III. It is a suspected variable star of unknown type with a maximum magnitude of 5.48.

It is radiating 110 times the Sun's luminosity from its photosphere at an effective temperature of 11,967 K. 63 Andromedae varies in brightness by about 0.05 magnitudes with a period of 4.189 days. This is believed to occur as it rotates. This type of variable star is known as an α2 Canum Venaticorum variable after the first example to be studied.

This is an evolved giant star with a stellar classification of G7 IIIa. It is a suspected variable star of unknown type, and is an X-ray source. The star is 370 million years old with 3.27 times the mass of the Sun. Having exhausted the hydrogen at its core, the star has expanded to 23 times the Sun's radius.

It is a suspected variable star and is currently on the asymptotic giant branch, which means it is generating energy at its core through the fusion of helium. The measured angular diameter of this star, after correction for limb darkening, is . At the estimated distance of Upsilon Aurigae, this yields a physical size of about 73 times the radius of the Sun.

Among the stars of this class, Omega Orionis was the first where the magnetic field was measured and found to be 1000 times that of the Earth. Omega Orionis is, like many Be stars, a variable star whose brightness varies 0.19 magnitudes. Also, small variations have been observed due to non-radial pulsations with periods of 0.97 and 2.19 days.

Two sets of independent follow-up spectroscopy data suggested that this was again another optical transient rather than a supernova, possibly an outbursting luminous blue variable star according to one spectrum, as earlier predicted from the nature of the candidate mid-infrared progenitor. The transient faded by 0.5-0.7 mag in 9 days, much faster than the 2008 transient in NGC 300.

31 Crateris is a binary star system in the constellation Corvus. Varying between apparent magnitudes 5.19 and 5.23 over 1.48 days, it has the variable star designation of TY Corvi. It is actually a remote system with a hot blue- white star of spectral type B1.5V and a companion about which little is known. The two stars orbit each other every 2.9631 days.

White Dwarf Stars, Steven D. Kawaler, in Stellar remnants, S. D. Kawaler, I. Novikov, and G. Srinivasan, edited by Georges Meynet and Daniel Schaerer, Berlin: Springer, 1997. Lecture notes for Saas-Fee advanced course number 25. ., p. 89. In 1985, this star was given the variable-star designation V777 Herculis, which is also another name for this class of variable stars.

V345 Carinae is a star in the constellation Carina. It has the Bayer designation E Carinae; V345 Carinae is the variable star designation. The star has a blue-white hue and is faintly visible to the naked eye with an apparent visual magnitude that fluctuates around +4.66. Its actual brightness varies from magnitude +4.67 to +4.78 with a period of 137.7 days.

V357 Carinae is a probable variable star; its brightness varies from magnitude +3.41 to +3.44 with a period of 6.74 days, which is its orbital period. It was classified as an eclipsing binary in Gaposchkin's original catalogue of variable stars, although the variability was often considered doubtful. It is now thought most likely to be a very shallow eclipsing binary.

Research in 1996 revealed that Sakurai's Object possessed the characteristics of a R Coronae Borealis variable star with the anomaly of Carbon-13 (13C) deficit. Also, the metallicity of Sakurai's object in 1996 was similar to that of V605 Aquilae in 1921. However, it is expected that Sakurai's object will grow in its metallicity to match that of V605 Aquilae.

W Phoenicis is a Mira variable, ranging from magnitude 8.1 to 14.4 over 333.95 days. A red giant, its spectrum ranges between M5e and M6e. Located 6.5 degrees west of Ankaa is SX Phoenicis, a variable star which ranges from magnitude 7.1 to 7.5 over a period of a mere 79 minutes. Its spectral type varies between A2 and F4.

This is an evolved K-type giant star with a stellar classification of K4 III, having used up its core hydrogen and has expanded to around 45 times the radius of the Sun. It is a suspected variable star, with a brightness that varies about 0.03 in magnitude. The relatively cool outer atmosphere has an effective temperature of 3999 K.

Abbot's solar cooker at Mount Wilson Observatory. Abbot began his astrophysics research focusing on solar radiation before proceeding to chart cyclic patterns found in solar variations. With this research he hoped to track solar constant in order to make weather pattern predictions. He believed that the sun was a variable star which effected the weather on Earth, which was criticized by many contemporaries.

The spectrum of FG Sagittae when it was first noted as a variable star was that of a blue supergiant. The first reliable spectral class is B0 in 1930. Extrapolation of the brightness and colour indices suggest it may have been an O3 star in 1890. It then steadily cooled, with the spectral class becoming as late as K2 in the 1980s.

DX Andromedae (often abbreviated to DX And) is a cataclysmic variable star in the constellation Andromeda. It has a typical apparent visual magnitude of 15.5 during the quiescent phase, but becomes brighter (up to a magnitude of 11.0) during outbursts recurring with a mean cycle length of 330 days, thus is classified as a dwarf nova of the SS Cygni type.

Wesselink was awarded a PhD in 1938 for research into the eclipsing variable star SZ Camelopardalis that used measurements of its brightness from 12000 photographic plates. He remained at Leiden University during the Nazi occupation in the Second World War, maintaining the functioning of the institution following the resignation of many senior staff members. He married Jeanette van Gogh in 1943.

CX CMa (CX Canis Majoris) is a blue variable star in the Canis Major constellation. Discovery of this variable is usually credited to German Astronomer Cuno Hoffmeister in 1931, although this remains uncertain. It is an eclipsing binary of Algol (detached) whose magnitude varies between 9.9 and 10.4 with a period of 0.95462500 day (22.911000 hour). The variability was first discovered in 1931.

R Corvi (R Crv) is a Mira variable star in the constellation Corvus, which ranges from a magnitude of 6.7 to 14.4 with a period of approximately 317 days. In the sky it appears close to Gamma Corvi and can be seen in the same binocular field. Extrapolating its luminosity from its period of 317 days yields a distance of 810 parsecs.

This star is relatively near to the Sun, at a measured distance of about 29 light years. It is a variable star with a small visual amplitude, only changing brightness between magnitudes 3.51 and 3.56. It is a suspected RS Canum Venaticorum variable, but this is still uncertain. δ Eridani is a subgiant star that has exhausted its core hydrogen.

WASP-10 is a star in the constellation Pegasus. The SuperWASP project has observed and classified this star as a variable star, perhaps due to the eclipsing planet. The star is likely older than Sun, has fraction of heavy elements close to solar abundance, and is rotating rapidly, being spun up by the tides raised by the giant planet on the close orbit.

Some studies suggest that this star is a luminous AGB star and a long-period variable, instead of a supergiant. It is classified in the General Catalogue of Variable Stars as a semiregular variable star of type SRb, indicating a cool pulsating giant star, with a possible period of 655 days. Its brightness varies between extremes of magnitude 7.7 and 9.2.

This is an evolved G-type giant star with a stellar classification of G8 III. It is classified as a BY Draconis type variable star. This is a chromospherically- active star with a longitudinal magnetic field strength of and an X-ray luminosity of . The activity and photometric variation of the star allow an estimate of its rotation period as 68 days.

HD 166 or V439 Andromedae (ADS 69 A) is a 6th magnitude star in the constellation Andromeda, approximately 45 light years away from Earth. It is a variable star of the BY Draconis type, varying between magnitudes 6.13 and 6.18 with a 6.23 days periodicity. It appears within one degree of the star Alpha AndromedaeAutostar Suite Astronomer Edition. CD-ROM. Meade, April 2006.

This variable star naming convention was developed by Friedrich W. Argelander. There is a widespread belief according to which Argelander chose the letter R for German rot or French rouge, both meaning "red", because many variable stars known at that time appear red. However, Argelander's own statement disproves this. By 1836, even the letter S had only been used in one constellation, Serpens.

A line from Beta Crucis through Delta Crucis passes somewhat to the north of NGC 3532. The cluster lies between the constellation Crux and the larger but fainter "False Cross" asterism. The 4th- magnitude Cepheid variable star x Carinae (V382 Car) appears near the southeast fringes, but it lies between the Sun and the cluster and is not a member of the cluster.

9 Cephei (9 Cep), also known as V337 Cephei, is a variable star in the constellation Cepheus. 9 Cephei was given the name V337 Cephei and classified as an α Cygni variable in 1967. It varies irregularly between magnitude 4.69 and 4.78. A study of the Hipparcos satellite photometry showed an amplitude of 0.56 magnitudes, but could find no periodicity.

31 Comae Berenices (31 Com) is a yellow giant star in the constellation Coma Berenices. Its apparent magnitude is about 4.9 and slightly variable. It is a rare FK Comae Berenices variable, a variable star that spins rapidly and has large starspots on its surface. It is currently in the Hertzsprung gap and its outer envelope has just begun convection.

Merope's mass is roughly 4.5 solar masses and has a radius more than 4 times as great as the Sun's. It is classified as a Beta Cephei type variable star and its brightness varies by 0.01 magnitudes. Surrounding Merope is the Merope Nebula (NGC 1435). It appears brightest around Merope and is listed in the Index Catalogue as number IC 349.

However, Palmer et al. (1968) had it classed as type A2IV, and thus it may be near or past its main sequence lifetime. It is a suspected variable star of unknown type that has been measured ranging in brightness from magnitude 5.78 down to 5.88. Upsilon Coronae Borealis has three times the mass of the Sun and about 1.5 times the Sun's radius.

Project and was co-chair of the transients and variable star group of the Large Synoptic Survey Telescope (LSST). Some of Bloom's current work focuses on the classification of astrophysical transients using machine-learning techniques. He suggested that GRB 110328A was due to a new class of relativistic outflow events from tidal disruption of a star by a massive black hole.

HD 223229 is a suspected variable star in the northern constellation of Andromeda. It is a double star consisting of a magnitude 6.11 primary and a magnitude 8.73 companion. The pair have an angular separation of 0.80″ along a position angle of 250°, as of 2009. The primary is a B-type subgiant star with a stellar classification of B3IV.

HD 102776, also known by its Bayer designation j Centauri (j Cen), is a star in the constellation Centaurus. j Centauri is a blue-white B-type main sequence dwarf. It is approximately 600 light years from Earth. It is classified as a suspected Gamma Cassiopeiae type variable star and with a visual magnitude varying from magnitude +4.30 to +4.39.

Chi Centauri (χ Cen, χ Centauri) is a star in the constellation Centaurus. χ Centauri is a blue-white B-type main sequence dwarf with a mean apparent magnitude of +4.36. It is approximately 510 light years from Earth. It is classified as a Beta Cephei type variable star and its brightness varies by 0.02 magnitudes with a period of 50.40 minutes.

Nu Herculis, Latinized from ν Herculis, is a binary and variable star in the constellation of Hercules. With an apparent magnitude of about 4.4, it is faintly visible to the naked eye. Parallax measurements made by the Hipparcos spacecraft put it at a distance of about 860 light years (260 parsecs). Nu Hercules is a binary with the two components separated by .

Given its age, Barnard's Star was long assumed to be quiescent in terms of stellar activity. In 1998, astronomers observed an intense stellar flare, showing that Barnard's Star is a flare star. Barnard's Star has the variable star designation V2500 Ophiuchi. In 2003, Barnard's Star presented the first detectable change in the radial velocity of a star caused by its motion.

SDSS J090744.99+024506.8 (SDSS 090745.0+024507) is a short-period variable star in the constellation Hydra. It has a Galactic rest-frame radial velocity of 709 km/s. Its effective temperature is 10,500 K (corresponding to a spectral type of B9) and its age is estimated to be at most 350 million years. It has a heliocentric distance of 71 kpc.

HD 153201 is a Bp star in the southern constellation of Ara. It is chemically peculiar star that displays an anomalous abundance of the element silicon in its spectrum. This is a suspected variable star of the type known as Alpha² Canum Venaticorum. There is a magnitude 9.86 companion star at an angular separation of 2.30″ along a position angle of 131°.

EV Carinae is a red supergiant and pulsating variable star of spectral type M4Ia in the constellation Carina. It is a semiregular variable star with its apparent magnitude varying between 7.4 and 9.0 in the visible band, making it only seen by binoculars or a telescope. Various periods have been identified, but the dominant one is around 347 days. EV Car is one of the largest known stars although its properties depend on its distance. In the late of the 20th century, EV Carinae, based on an assumed distance of 4.2 kpc, was found to be an extremely luminous and large supergiant star with an unusual luminosity between 550,000 and 675,000 times that of the Sun (), which would imply radii of 2,880 to 3,190 times the Sun's radius () at a temperature of 2,930 K, making it larger than the orbit of Saturn.

Located south of Kochab and Pherkad towards Draco is RR Ursae Minoris, a red giant of spectral type M5III that is also a semiregular variable ranging from magnitude 4.44 to 4.85 over a period of 43.3 days. T Ursae Minoris is another red giant variable star that has undergone a dramatic change in status—from being a long period (Mira) variable ranging from magnitude 7.8 to 15 over 310–315 days to a semiregular variable. The star is thought to have undergone a shell helium flash—a point where the shell of helium around the star's core reaches a critical mass and ignites—marked by its abrupt change in variability in 1979. Z Ursae Minoris is a faint variable star that suddenly dropped 6 magnitudes in 1992 and was identified as one of a rare class of stars—R Coronae Borealis variables.

The angular diameter of W Orionis has been measured using interferometry and a value of 9.7 mas is found. Although it is known to be a pulsating variable star, no changes in the diameter were seen. Technetium has not been detected in W Orionis, an unexpected result since this s-process element should be dredged up in all thermally-pulsating AGB stars and especially in carbon stars.

At optical wavelengths, the brightness changes were almost undetectable. It was classified as a flare star and given the variable star designation FI Virginis. Because of the low rate of flare activity, it is thought to be a magnetically evolved star. That is, there is some evidence that the magnetic braking of the star's stellar wind has lowered the frequency of flares, but not the net yield.

TW Piscis Austrini (also Fomalhaut B) is a dwarf star in the constellation Piscis Austrinus. It lies relatively close to the Sun, at an estimated distance of 24.9 light years. To an observer on Earth the star is visually separated from its larger companion Fomalhaut A by 2 degrees - the width of four full moons. The TW in the name is astronomical nomenclature for a variable star.

However, Scarfe (1985) noted that these observations may instead be due to normal observational error. The common proper motion companion, component B, is a magnitude 10.11 star at an angular separation of along a position angle of 35°. It has an estimated orbital period of 3,371 years. According to Hoffleit (1991), if this is a variable star it may account for the observations of Bakos (1983).

An analysis of Hipparcos photometry showed an amplitude of 0.0168 magnitudes and a period of 2.65 days. The statistical signal was strong enough for the variability to be very likely, but 5 Persei has not formally been catalogued as a variable star. 5 Persei has two nearby companions, a 12th magnitude star 5.7 arc-seconds away and a 13th magnitude star one arc-minute away.

BI Cyg is a slow irregular variable star classified as type Lc, an irregular supergiant. Its brightness changes between extremes of magnitude 8.4 and 9.9. Frequency analysis of its light curve shows no significant periods. BI Cyg is one of the largest known stars with a radius around based on the assumption of an effective temperature of 3,575 K and a bolometric luminosity of .

70 Ophiuchi is a variable star with a magnitude range for the two stars combined of 4.00 to 4.03. The type of variability is uncertain and it is not clear which of the two components causes the variations. It has been suspected of being either a BY Draconis variable or an RS Canum Venaticorum variable, and a period of 1.92396 days has been measured.

Beta Cephei (β Cep) variables (sometimes called Beta Canis Majoris variables, especially in Europe)Variable Star Of The Season, Winter 2005: The Beta Cephei Stars and Their Relatives, John Percy, AAVSO. Accessed October 2, 2008. undergo short period pulsations in the order of 0.1–0.6 days with an amplitude of 0.01–0.3 magnitudes (1% to 30% change in luminosity). They are at their brightest during minimum contraction.

Nu Orionis (ν Orionis) is a binary star system in the northeastern part of the constellation Orion. It should not be confused with the variable star NU Orionis. Nu Orionis has an apparent visual magnitude of 4.42, which is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 0.00632 arcseconds, the distance to this system is roughly 520 light years.

IX Carinae (IX Car) is a red supergiant and pulsating variable star of spectral type M2Iab in the constellation Carina. It is a member of the Carina OB1 association along the Carina Nebula. It is one of the largest stars with a radius of . If placed at the center of the Solar System, it would extend close to the orbit of the outer Asteroid Belt Jupiter.

QU Normae, also known as HR 6131, is a blue supergiant star in the constellation Norma. It is also a variable star, thought to be an α Cyg variable. The apparent magnitude of QU Normae varies somewhat irregularly between 5.27 and 5.41. The General Catalogue of Variable Stars quotes a period of 4.818 days, but other research only shows likely periods longer than 10 days.

Images from the Hubble Space Telescope have shown districts of very high blue straggler densities, suggesting that the center of the cluster is likely to have a very high capture and collision rate. On May 21, 1860, a nova was discovered in M80 that attained a magnitude of +7.0. The nova, variable star designation T Scorpii, reached an absolute magnitude of −8.5, briefly outshining the entire cluster.

This object is an aging red giant star with a stellar classification of M0.5III. After exhausting the supply of hydrogen at its core, the star cooled and expanded off the main sequence, and now has around 51 times the Sun's radius. It is radiating 628 times the luminosity of the Sun from its photosphere at an effective temperature of 4,033 K. This is a suspected variable star.

The star radiates 57.5 times the solar luminosity from its outer atmosphere at an effective temperature of 4,876 K. It is catalogued as a suspected variable star. In Chinese, (), meaning Grandson, refers to an asterism consisting of κ Columbae and θ Columbae. 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, .

Centaurus is home to many variable stars. R Centauri is a Mira variable star with a minimum magnitude of 11.8 and a maximum magnitude of 5.3; it is about 1,250 light-years from Earth and has a period of 18 months. V810 Centauri is a semiregular variable. BPM 37093 is a white dwarf star whose carbon atoms are thought to have formed a crystalline structure.

The fourth and fifth components are a binary red dwarf system that is 14,000 AU distant from the other three stars. ADS 9731 is an even rarer multiple system in the constellation, composed of six stars, two of which are spectroscopic binaries. Corona Borealis is home to two remarkable variable stars. T Coronae Borealis is a cataclysmic variable star also known as the Blaze Star.

R Centauri (R Cen) is a Mira variable star in the constellation Centaurus. It is approximately 1,300 light years from Earth. R Centauri is a Mira variable and its brightness varies from magnitude +5.2 to +11.5 with a period of about 500 days. It used to have an unusual double-peaked light curve, but by 2001 this had reverted to an almost normal single-peaked curve.

The nebula surrounds the variable star RU Coronae Australis, which has an average apparent magnitude of 12.9 and is a WC class Wolf–Rayet star. IC 1297 is small, at only 7 arcseconds in diameter; it has been described as "a square with rounded edges" in the eyepiece, elongated in the north-south direction. Descriptions of its color encompass blue, blue-tinged green, and green-tinged blue.

This is a BY Draconis variable star that undergoes brightness variations due to stellar activity. Differential rotation causes changes to the periodicity of the variation depending on the latitude of the activity. X-ray emission has been detected from AK Leporis, and it is located at or near a radio source. Infrared observation of this star shows a large excess at a wavelength of 24 µm.

NU Pavonis is a variable star in the southern constellation of Pavo. With a nominal apparent visual magnitude of 4.95, it is a faint star but visible to the naked eye. The distance to NU Pav, as determined from its annual parallax shift of as seen from Earth's orbit, is around 460 light years. It is moving closer with a heliocentric radial velocity of −10 km/s.

Delta Librae is an Algol-type eclipsing variable star, 304 lightyears from Earth. It has a period of 2 days, 8 hours; its minimum magnitude of 5.9 and its maximum magnitude is 4.9. FX Librae, designated 48 Librae, is a shell star of magnitude 4.9. Shell stars, like Pleione and Gamma Cassiopeiae, are blue supergiants with irregular variations caused by their abnormally high speed of rotation.

TZ Cassiopeaie (TZ Cas, HIP 117763, SAO 20912) is a variable star in the constellation Cassiopeia with an apparent magnitude of around +9 to +10. It is approximately 8,000 light-years away from Earth. The star is a red supergiant star with a spectral type of M3 and a temperature below . TZ Cassiopeiae was reported as being variable by Williamina Fleming and published posthumously in 1911.

BY Draconis variables are variable stars of late spectral types, usually K or M, and typically belong to the main sequence. The name comes from the archetype for this category of variable star system, BY Draconis. They exhibit variations in their luminosity due to rotation of the star coupled with starspots, and other chromospheric activity. Resultant brightness fluctuations are generally less than 0.5 magnitudes.

RT Andromedae is a variable star in the constellation of Andromeda. The system is estimated to be 322 light-years (98.7 parsecs) away. RT Andromedae is classified as a RS Canum Venaticorum variable, a type of close eclipsing binary star. It varies from an apparent visual magnitude of 9.83 at minimum brightness to a magnitude of 8.97 at maximum brightness, with a period of 0.6289216 days.

9 Equulei is an M-type star in the constellation Equuleus. It is an asymptotic giant branch (AGB) star, a star that has exhausted its core helium and is now fusing both hydrogen and helium in shells outside the core. It is also a suspected variable star with an amplitude of about 0.05 magnitudes. The spectral type is M2IIIa, meaning it is a relatively cool giant star.

SX Centauri is a variable star in the constellation Centaurus. An RV Tauri variable, its light curve alternates between deep and shallow minima, varying its apparent magnitude from 9.1 to 12.4. From the period-luminosity relationship, it is estimated to be around 1.6 kpc (5200 light-years) from Earth. Gaia Data Release 2 gives a parallax of 0.2175 mas, corresponding to distance of about .

377-381 in White Dwarfs and Variable Degenerate Stars, IAU Colloquium #53, ed. H. M. van Horn and V. Weidemann, Rochester: University of Rochester Press, 1979. and it was given the variable star designation GW Vir in 1985.The 67th Name-List of Variable Stars, P. N. Kholopov, N. N. Samus, E. V. Kazarovets, and N. B. Perova, Information Bulletin on Variable Stars, #2681, March 8, 1985.

The addition of a home observatory at Morgan Hill culminated years of interest in astronomy as a hobby. Barns was a charter member of the Association of Variable Star Observers and member of the American Astronomical Society. For the former organization, he cataloged their membership, library, and lantern slide collection. Barns was similarly active in the British Astronomical Association and the Astronomical Society of the Pacific.

377-381 in White Dwarfs and Variable Degenerate Stars, IAU Colloquium #53, ed. H. M. van Horn and V. Weidemann, Rochester: University of Rochester Press, 1979. and was given the variable star designation GW Vir in 1985.The 67th Name-List of Variable Stars, P. N. Kholopov, N. N. Samus, E. V. Kazarovets, and N. B. Perova, Information Bulletin on Variable Stars, #2681, March 8, 1985.

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.

HD 187923 is a suspected variable star in the equatorial constellation of Aquila. It is a dim star that is just visible to the naked eye, having an apparent visual magnitude of 6.148. Based upon an annual parallax shift of , it is located 88 light years away. The star is moving closer to the Earth with a heliocentric radial velocity of −20.7 km/s.

In 1956 Daniel Overbeek became the chairman of the Transvaal Centre of the Astronomical Society of Southern Africa (ASSA). He was elected the president of the ASSA twice: in 1961 and 1999. In 1984 he was awarded the Gill Medal, the highest ASSA honour. The American Association of Variable Star Observers awarded him with the Merit Award in 1986 and the Director's Award in 1994.

He became known as a kindly landlord but also as a scholar and intellectual. From 1858 He started contributing notes on astronomy to local newspapers. At Millbrook he built what The Tuam Herald called a large wooden house with a sliding roof, which formed his first observatory. On 12 May 1866 he discovered the variable star T Coronae Borealis in the constellation Corona Borealis.

EF Eridani (abbreviated EF Eri, sometimes incorrectly referred to as EF Eridanus) is a variable star of the type known as polars, AM Herculis stars, or magnetic cataclysmic variable stars. Historically it has varied between apparent magnitudes 14.5 and 17.3, although since 1995 it has generally remained at the lower limit. The star system consists of a white dwarf with a substellar-mass former star in orbit.

This is listed as an eclipsing binary system with a period of 47.9 days and has the variable star designation RR Arietis. During each eclipse of the primary star, the magnitude of the system decreases by 0.40. The eclipse of the secondary reduces the magnitude by 0.35. The primary component of the system is an evolved giant star with a stellar classification of K1 III.

20 Aquilae, abbreviated 20 Aql, is an irregular variable star in the equatorial constellation of Aquila. 20 Aquilae is its Flamsteed designation. It ranges in magnitude from a peak of 5.33 down to 5.36, which is bright enough for the star to be visible to the named eye. The estimated distance to this star is around 920 light years, based upon an annual parallax shift of .

The primary, component A, has a stellar classification of B8 IIIp, suggesting it is a B-type giant star. It a mercury-manganese star, a type of chemically peculiar star showing large overabundances of those two elements in the outer atmosphere. It is classified as an Alpha2 Canum Venaticorum type variable star and its brightness varies from magnitude +5.22 to +5.27 with a period of 5 days.

This star system was catalogued in the 1862 Bonner Durchmusterung ("Bonn astrometric Survey") as BD +18°4794B. It later appeared in Pickering's 1908 Harvard Revised Photometry Catalogue as HR 8210. The designation "IK Pegasi" follows the expanded form of the variable star nomenclature introduced by Friedrich W. Argelander. Examination of the spectrographic features of this star showed the characteristic absorption line shift of a binary star system.

56 Orionis is a single, variable star in the equatorial constellation of Orion. It has an orange hue and is faintly visible to the naked eye with an apparent visual magnitude that fluctuates around 4.76. The star is located at a distance of approximately 1,130 light years from the Sun based on parallax. It is drifting further away with a radial velocity of +11 km/s.

HK Aquarii (Gliese 890) is a variable star—technically a BY Draconis variable—noteworthy for being unusually active for an isolated red dwarf; it rotates rapidly, generating a strong magnetic field that creates large starspots and powerful flares. These are characteristic of very young stars; although it is not close to any youthful open cluster, it is a possible ejected member of the Pleiades.

University of Bonn researchers made fundamental contributions in the sciences and the humanities. In physics researchers developed the quadrupole ion trap and the Geissler tube, discovered radio waves, were instrumental in describing cathode rays and developed the variable star designation. In chemistry researchers made significant contributions to the understanding of alicyclic compounds and Benzene. In material science researchers have been instrumental in describing the lotus effect.

HD 94510 is a suspected variable star with a brightness that has been measured varying from magnitude 3.75 down to 3.80. It has an estimated 1.60 times the mass of the Sun and has expanded to nearly eight times the Sun's radius. The star is radiating 31 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,955 K.

HD 96919, also known by its Bayer designation of z2 Carinae and the variable star designation of V371 Carinae, is a blue supergiant star in the constellation Carina. It lies near the Carina Nebula and at a comparable distance. V371 Car is an α Cyg variable, erratically pulsating and changing brightness by a few hundredths of a magnitude. Periods of 10–80 days have been identified.

HD 91942 is a single variable star in the constellation Carina. It has the Bayer designation r Carinae, while HD 91942 is the identifier from the Henry Draper catalogue. This orange-hued object is visible to the naked eye with an apparent visual magnitude of 4.45. Based on parallax measurements, it is located at a distance of approximately 1,180 light years from the Sun.

As a "computer" at Harvard College Observatory, beginning immediately after college in 1893,"Alumnae Notes" The Wellesley Magazine (November 1893): 114. Woods worked with Harlow Shapley and Annie Jump Cannon. She studied photographic plates to discover dozens of variable stars during her career. She attended the meeting of the American Association of Variable Star Observers (AAVSO) in 1916, when it was held at Harvard.

V376 Carinae is a binary star system in the southern constellation of Carina. It has the Bayer designation b1 Carinae; V376 Carinae is the variable star designation. The system is visible to the naked eye as a faint point of light with a combined apparent magnitude of +4.69. The distance to this system from the Sun is approximately 650 light years based on parallax.

ALMA image of the dust shells around U Antliae U Antliae (U Ant) is a variable star in the constellation Antlia. It is a carbon star surrounded by two thin shells of dust. U Antliae is an extremely red C-type carbon star. These cool stars on the asymptotic giant branch are further reddened by strong mass loss and dust that forms around the star.

HD 34626, also known as MZ Aurigae, is an unusual variable star in the northern constellation of Auriga. It varies in brightness by 0.1 magnitude over time scales of 8 to 12 hours, but these variations are not periodic. This indicates the variability is not caused by ellipsoidal effects, and the nature of the variability remains unknown. It is a Be star and is rotating rapidly.

106 Herculis is a variable star in the northern constellation Hercules. It is visible to the naked eye as a faint, red-hued point of light with a baseline apparent visual magnitude of 4.96. Based on its parallax, it is estimated to lie away from the Sun. The star is moving closer to the Earth with a heliocentric radial velocity of -35 km/s.

V352 Aurigae is a variable star in the northern constellation of Auriga. According to the Bortle scale, an apparent magnitude of 6.14 means that it is faintly visible to the naked eye from dark rural skies. It is a variable of Delta Scuti-type, which suggests that the variability is caused by the rotation of the host star in combination with localized regions of activity.

HD 32188 is suspected variable star in the northern constellation of Auriga, and is positioned roughly in between Eta and Zeta Aurigae. It has a white hue and is just barely visible to the naked eye with an apparent visual magnitude that fluctuates around 6.08. The distance to this star is approximately 3,000 light years, based on parallax. It has an absolute magnitude of −2.87.

In 2005 she became the editor-in-chief of the astronomical journal Publications of the Astronomical Society of the Pacific (PASP). She is also very active in professional-amateur collaboration, especially in conjunction with the American Association of Variable Star Observers, for whom she has served both as an officer on the board (2003-2009) and, for the term 2007-09, as President of the organization.

It is a variable star with an active chromosphere and is a source of X-ray emission. HD 189245 is spinning rapidly with a projected rotational velocity of 72.6 km/s. Gyrochronology indicates this is a young star with an estimated age of 500 million years. However, the amount of X-ray emission suggests an even younger star that is roughly 100 million years old.

Nu Cephei (ν Cephei) is a class A2, fourth-magnitude supergiant star in the constellation Cepheus. It is a white pulsating α Cygni variable star located about 4,700 light-years from Earth. ν Cephei is a member of the Cepheus OB2 stellar association, which includes stars such as μ Cephei and VV Cephei. It began life as an approximately star around eight million years ago.

The angular diameter of Aldebaran has been measured many times. The value adopted as part of the Gaia benchmark calibration is . It is 44 times the diameter of the Sun, approximately 61 million kilometres. Aldebaran is a slightly variable star, assigned to the slow irregular type LB. The General Catalogue of Variable Stars indicates variation between apparent magnitude 0.75 and 0.95 from historical reports.

S Coronae Borealis was discovered to vary in brightness by German amateur astronomer Karl Ludwig Hencke in 1860. It was classified as a long period variable star as other similar objects were discovered, and later as a Mira variable. The maximum range of variation is from magnitude 5.8 to 14.1 although individual maxima and minima can vary in brightness. The period of 360 days is fairly predictable.

One thousand and forty light- years from Earth, Beta Doradus has a period of 9 days and 20 hours. R Doradus is one of the many variable stars in Dorado. S Dor, 9.721 hypergiant in the Large Magellanic Cloud, is the prototype of S Doradus variable stars. The variable star R Doradus 5.73 has the largest known apparent size of any star other than the Sun.

Chandra sent his observatory report to Edward Charles Pickering who was then a researcher of Harvard Space Observatory. Pickering gave him a lot of inspiration and sent some books to him. He invited him to become a member of 'American Association of Variable Star Observers (AAVSO)'. He became a member of AAVSO which, in 1926, gave him a 6-inch aperture telescope directly sent from USA.

HD 97048 or CU Chamaeleontis is a Herbig Ae/Be star away in the constellation Chamaeleon. It is a variable star embedded in a dust cloud containing a stellar nursery, and is itself surrounded by a dust disk. HD 97048 is a young star still contracting towards the main sequence. Its brightness varies between magnitudes 8.38 and 8.48 and it is classified as an Orion variable.

Delta Librae, Latinized from δ Librae, is a variable star in the constellation Libra. It has the traditional name Zuben Elakribi, a variant of the traditional name of Gamma Librae.Bečvář, A., Atlas Coeli II Atlas Coeli II- Catalog, Ceskoslovenské Akademie Ved, Praha,1959. With μ Vir it forms one of the Akkadian lunar mansions Mulu-izi (meaning "Man-of-fire"Brown Jr., R., (1891).

Symbiotic binaries are often divided into two sub-types based on the nature of the continuum in their spectra. S-type systems have a stellar continuum since the giant component is not obscured. D-type systems are surrounded by optically thick dusty nebulosity and the star itself is not directly visible. D-type systems tend to contain a Mira variable or other long period variable star.

RU Cam was reported as a new variable star in 1907. It was quickly recognised as one of the Cepheid class of variable stars. The first detailed study of the spectrum of RU Cam showed that it changed during the brightness variations. From partway down the descending branch of the light curve to just after minimum brightness, the spectrum is class R with hydrogen absorption lines.

Another ageing star, Kappa Telescopii is a yellow giant with a spectral type G9III and apparent magnitude of 5.18. Around 1.87 billion years old, this star of around 1.6 solar masses has swollen to 11 times the Sun's diameter. It is approximately 293 light- years from Earth, and is another optical double. Xi Telescopii is an irregular variable star that ranges between magnitudes 4.89 and 4.94.

Location of HR 6819 the star system containing the black hole. Telescopium is also host to the first known visible star system with a black hole. QV Telescopii, also designated HR 6819, is a triple star system, which is visible to the unaided eye as a variable star with apparent magnitude 5.32 to 5.39. It is located in Telescopium near its SW corner with Ara and Pavo.

It has an absolute magnitude of −1.55. This is an evolved K-type giant star with a stellar classification of K5 III, which means it has used up its core hydrogen and has expanded. At present it has 40 times the radius of the Sun. It is a variable star of unknown type, with an amplitude of 0.008 in visual magnitude and a period of 4.82 days.

This is an aging red giant with a stellar classification of M3 IIIa, currently on the asymptotic giant branch. It is classified as a semiregular variable star of type SRb and its brightness varies from magnitude +5.41 to +5.75 with a period of 40 days. The star is radiating around 2,455 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,574 K.

However, they could not help but notice the resemblance of the constellation Cassiopeia to the mouth of Old Grabby. Martians had a cleft jaw which gave their mouths a characteristic "W" shape which they naturally transferred to their mythical beings. Not far away was the Martian North pole star, Delta Cephei, which is a variable star. Its changing brightness was likened to the breathing of a Sleeper.

This star is classified as an Alpha Cygni-type variable star that undergoes periodic non-radial pulsations, which cause its brightness to cycle from magnitude +2.93 to +3.08 over a 24.44 day interval. It is losing mass from its stellar wind at the rate of around times the mass of the Sun per year, or the equivalent of the Sun's mass every 500 million years.

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.

This magnetic field varies as it rotates and in 1968 the visual brightness of the star was shown to vary regularly over about four days. 15 Cancri was given the variable star designation BM Cancri in 1972 as a member of the α2 CVn class of variable stars. The period has since been measured more accurately at , believed to be the rotational period of the star.

It is classified as an SX Arietis type variable star and its magnitude varies by less than a tenth of a magnitude. The luminosity of α Scl is around 1,500 times that of the Sun while its surface temperature is 13,600 K. The radius of Alpha Sculptoris is calculated to be seven times solar while its mass is five times that of the Sun.

RR Coronae Borealis (RR CrB, HD 140297, HIP 76844) is a M3-type semiregular variable star located in the constellation Corona Borealis with a parallax of 2.93mas being a distance of . It varies between magnitudes 7.3 and 8.2 over 60.8 days. Located around 1228 light-years distant, it shines with a luminosity approximately 2180 times that of the Sun and has a surface temperature of 3309 K.

Theta Tauri A has a mean apparent magnitude of +3.40. It is classified as a Delta Scuti type variable star and its brightness varies from magnitude +3.35 to +3.42 with a period of 1.82 hours. Its primary component, Theta Tauri Aa, is a white A-type giant. The secondary, Theta Tauri Ab, is of the 6th magnitude and is 0.005 arcseconds, or at least 2 AU, distant.

This can be done by interpolating the brightness of the variable between two comparison stars, or by individually estimating the magnitude difference between the variable and several different comparisons. Repeating the observation on different nights allows a light curve to be produced showing the variation in brightness of the star. In practice, visual variable star estimates from many observers are statistically combined to produce more accurate results.

17 Leporis is a binary star system in the southern constellation of Lepus.§1, Verhoelst, van Aarle, and Acke, 2007. It has an overall apparent visual magnitude which varies between 4.82 and 5.06, making it luminous enough to be visible to the naked eye as a faint star. The variable star designation for this system is SS Leporis, while 17 Leporis is the Flamsteed designation.

1 Lyncis is a single star in the northern constellation of Lynx. It is also known by its variable star designation of UW Lyncis; 1 Lyncis is the Flamsteed designation. This object is visible to the naked eye as a faint, reddish-hued star with an apparent visual magnitude of 4.95. It is moving further from the Earth with a heliocentric radial velocity of 12 km/s.

OP Andromedae is a variable star in the constellation Andromeda. Varying between magnitudes 6.27 and 6.41 over 2.36 days, it has been classified as an RS Canum Venaticorum variable, but there has not been any proof of binarity, yet. It's a red giant star which spectral classification is K1III. OP Andromedae is one of the few red giant stars where it was detected an overabundance of 7Li.

HD 125823, also known as V761 Centauri or a Centauri, is a star in the constellation Centaurus. It is a blue-white B-type giant with a mean apparent magnitude of +4.41. It is approximately 460 light years from Earth. It is classified as an SX Arietis type variable star and its brightness varies from magnitude +4.38 to +4.43 with a period of 8.82 days.

UY Scuti (BD-12°5055) is a red supergiant star in the constellation Scutum. It is considered one of the largest known stars by radius and is also a pulsating variable star, with a maximum brightness of magnitude 8.29 and a minimum of magnitude 10.56. It has an estimated radius of ; thus a volume nearly 5 billion times that of the Sun. It is approximately from Earth.

HD 33579 is a white/yellow hypergiant and one of the brightest stars in the Large Magellanic Cloud (LMC). It is a suspected variable star. HD 33579 lies in a part of the Hertzsprung–Russell diagram referred to as the Yellow Evolutionary Void because stars with that combination of luminosity and temperature are extremely unstable. They either expand to become cooler or shed their outer layers completely to become hotter.

He told his superior Carl Lampland but the discovery was not reported further. Variable star observer David Levy found out about the object while researching and writing Tombaugh's biography in 1988. He discovered a further nine outbursts after inspecting 260 photographic plates that spanned the next sixty years, and then set about watching the star. After almost 70 nights, he finally saw an outburst on March 23, 1990.

HD 170657 is a star in the constellation Sagittarius. It is located at a distance of about 43 light years. It has 0.79 solar masses and is a suspected variable star that varies in apparent magnitude from 6.82−6.88. When observed with the Spitzer Space Telescope, this star did not display an excess emission of infrared radiation, which may otherwise indicate the presence of an orbiting debris disk.

Son of the astronomer Nathaniel Pigott, Pigott's work focused on variable stars. Educated in France with a mother from Louvain, the family moved to York in 1781. Despite their significant age difference, he was a friend and collaborator of John Goodricke (his distant cousin) until the latter's untimely death at the age of 21 in 1786. In 1784, Pigott informed the Royal Society of his discovery of a new variable star.

An SX Phoenicis variable is a type of variable star. These stars exhibit a short period pulsation behavior that varies on time scales of 0.03–0.08 days (0.7–1.9 hours). They have spectral classifications in the range A2-F5 and vary in magnitude by up to 0.7. Compared to the Sun, these stars have a lower metallicity, which means they have a reduced abundance of elements other than hydrogen and helium.

X Trianguli Australis is a star in the southern constellation Triangulum Australe. It is a red-hued carbon star with an average apparent magnitude of +5.89. It is approximately 1173 light years (360 parsecs) from Earth, though this could vary by up to 200 light years. It is a semi-regular variable star with two periods of around 385 and 455 days, and is of spectral type C5.5(Nb).

It ranges from magnitudes 5.03 to 6.05. Its designation is from the variable star designation developed by German astronomer Friedrich Wilhelm Argelander. It is a cool star, with estimates of its surface temperature ranging from 2200 to 2700 Kelvin. A giant star, its diameter is 400 times that of the sun, and if placed at the center of the Solar System would stretch out to 30% further than Mars' orbit.

This is an aging red giant star with a stellar classification of M3 III, indicating it has exhausted the hydrogen at its core and evolved off the main sequence. It is a candidate long-period variable star and has been given the designation YY Psc. Its varies in brightness between magnitudes 4.31 and 4.41 with no clear period. Possible periods of 23.1, 32.0, 53.6, and 167.8 days have been identified.

At that distance, the visual magnitude is diminished by an extinction factor of 0.08 due to interstellar dust. This is a red giant star on the asymptotic giant branch, with a stellar classification of M2 III. It is a suspected variable star, although the evidence is considered "doubtful or erroneous". If it does exist, the variability is small with an amplitude of 0.05 magnitude and a timescale of around 30 days.

The white dwarf strips matter off its companion, forming an accretion disk which periodically ignites and erupts. The star system has a magnitude of 15.9 when quiescent, brightening to 12.7 in outburst. SZ Crateris is a magnitude 8.5 BY Draconis type variable star. It is a nearby star system located about 42.9 ± 1.0 light-years from the Sun, and is a member of the Ursa Major Moving Group.

OU Andromedae (also HR 9024) is a rotationally variable star in the constellation Andromeda. Varying between magnitudes 5.87 and 5.94, it has been classified as an FK Comae Berenices variable, but the classification is still uncertain. It has a spectral classification of G1IIIe, meaning that it is a giant star that shows emission lines in its spectrum. It is also likely in its horizontal branch phase of evolution.

In 1901, κ Pavonis was reported to be a variable star with a magnitude range of 3.8 to 5.2 with a period of 9.0908 days. Further observations revealed radial velocity variations in time with the brightness variations, but this was assumed to indicate a spectroscopic binary system. The brightness variations were then interpreted as eclipses. Less than 10 years later, was κ Pav was listed as a likely Cepheid variable.

BO Carinae, also known as HD 93420, is an irregular variable star in the constellation Carina. BO Car has a maximum apparent magnitude of +7.18. Its distance and membership is uncertain, but its possible membership to the star cluster Trumpler 15 allows a distance estimate of approximately (). The Gaia Data Release 2 parallax of suggests a closer distance, but the value is considered unreliable due to excess astrometric noise.

At present it has 67 times the radius of the Sun. It is a variable star of uncertain type, changing brightness with an amplitude of 0.0058 in visual magnitude over a period of 8.5 days. The star radiates 927 times the luminosity of the Sun from its bloated photosphere at an effective temperature of 3,931 K. A magnitude 10 visual companion is located at an angular separation of .

TT Aquilae (TT Aql) is a Classical Cepheid (δ Cep) variable star in the constellation Aquila. The visual apparent magnitude of TT Aql ranges from 6.52 to 7.65 over 13.7546 days. The light curve is asymmetric, with the rise from minimum to maximum brightness only taking half the time of the fall from maximum to minimum. TT Aql is a yellow-white supergiant around five thousand times brighter than the sun.

The brightness changes are due to starspots and chromospheric activity combined with the rotation of the star. It has been given the variable star designation EE Leonis. Like the vast majority of stars in the Solar neighborhood, Gliese 402 is a dim red dwarf. With an apparent magnitude +11.66, it is far too dim to be seen with the naked eye; it can only be seen with a telescope.

In 1965 it was designated a classical Cepheid variable star with a brightness that ranged from 5.10 to 5.12, but is now considered to be (most likely) constant. It displays an infrared excess, suggesting a circumstellar disk is orbiting at a radius of with a mean temperature of 90 K. The cooler secondary companion has a class of F3 V. The system appears to be a source of X-ray emission.

He was also a multiple AAVSO Observer awardee: in 1994 for making 100,000 variable star observations, in 1997 for 200,000 and in 1999 for 250,000 observations. In 1995 he received the Christos Papadopoulos Trophy of the Transvaal Centre of the ASSA. He also won the Amateur Achievement Award of the Astronomical Society of the Pacific in 1996. The Mars-crosser asteroid 5038 Overbeek was named in his honour in 2000.

UX Arietis is a triple star system located in the northern zodiacal constellation of Aries. Based upon parallax measurements from the Hipparcos satellite, it is roughly 168 light years away. The primary, component Aa, is a variable star of the RS CVn type. The variability of the star is believed due to a combination of cool star spots and warm flares, set against the baseline quiescent temperature of the stellar atmosphere.

It is a Delta Scuti type variable star, with a dominant pulsation period of 0.1881 days and an amplitude of 0.016 in magnitude. David and Hillenbrand (2015) found an average mass for this star of 1.61 times the mass of the Sun, whereas Zorec and Royer (2012) list a much higher mass estimate of . It is about 356 million years old with a projected rotational velocity of 222 km/s.

S Trianguli Australis is a yellow-white hued variable star in the constellation Triangulum Australe. It is a dim star near the lower limit of visibility with the naked eye, having a typical apparent visual magnitude of 6.41. Based upon an annual parallax shift of , it is located 3,030 light years from the Earth. A Classical Cepheid variable, its apparent magnitude ranges from 5.95 to 6.81 over 6.32344 days.

Nebula IC 405 around AE Aurigae AE Aurigae is a blue O-type main sequence dwarf with a mean apparent magnitude of +6.0. It is classified as an Orion type variable star and its brightness varies irregularly between magnitudes +5.78 and +6.08. It is approximately 1,300 light-years from Earth. AE Aur is a runaway star that might have been ejected during a collision of two binary star groups.

31 Aquilae has an apparent visual magnitude of 5.16, making it bright enough to be seen with the naked eye in dark skies. The annual parallax shift of 65.89 mas yields a distance estimate of from Earth. It is a variable star with a magnitude change of less than 0.02. With a stellar classification of G8 IV, the luminosity class of IV indicates this is a subgiant star.

The spectrum of this star matches a stellar classification of F0 III, with the luminosity class of III indicating this is most likely an evolved giant star. The variability of this star was discovered by Michel Breger in 1969. It was revealed to be a Delta Scuti-type pulsating variable star with at least two periods of pulsation. The known periods have frequencies of 6.68 and 7.12 cycles per day.

It has expanded to around 51–88 times the Sun's radius and is radiating 447–fold the luminosity of the Sun. This energy is being emitted from its outer atmosphere at an effective temperature of 5,478 K, giving it the golden-hued glow of a G-type star. It is a suspected variable star. The companion is a magnitude 7.9 star with an angular separation of 120.1 arcseconds from the primary.

QX Andromedae (often abbreviated to QX And) is an eclipsing binary in the constellation Andromeda. It varies from a maximum apparent visual magnitude of 11.28 to a minimum of 11.50. Since it is impossible to specify the onset time of the eclipses, it is classified as a W Ursae Majoris variable star. It is also observed as an X-ray source and is a member of the open cluster NGC 752.

V1315 Aquilae is a cataclysmic variable star located in the constellation of Aquila. It is a type of cataclysmic variable known as a nova-like variable (NL), specifically a SW Sextantis star. Nova-like variables such as these SW Sextantis stars are characterized as having non-magnetic white dwarfs and do not undergo dwarf-nova eruptions. There is some evidence that SW Sextantis stars may contain a magnetic white dwarf.

C1 Centauri is a single star in the southern constellation of Centaurus. It has the variable star designation V763 Centauri, while C1 Centauri is the Bayer designation. The star has a red hue and is dimly visibly to the naked eye with an apparent visual magnitude that fluctuates around +5.64. It is located at a distance of approximately 600 light years based on parallax, and has an absolute magnitude of −1.05.

It is also listed as a suspected variable star. The magnetic activity cycle for this star shows a period of 122 days − much shorter than the solar cycle. Tau Boötis B (with a capital B, as opposed to the planet) is a dim red dwarf orbiting the primary star at a distance of 220 AU. One orbit around the primary would take approximately two and a half thousand years to complete.

Component E is an unusual variable star, classified as an SX Arietis variable and also known as V1030 Orionis. It is helium-rich, has a strong magnetic field, and varies between magnitudes 6.61 and 6.77 during a 1.19 day period of rotation. It has a spectral type of B2 Vpe. The variability is believed to be due to large-scale variations in surface brightness caused by the magnetic field.

XTE J1118+480 was discovered using the All-Sky Monitor on the Rossi X-Ray Timing Explorer satellite after it detected an outburst from the system on March 29, 2000. XTE is the standard designation for objects discovered by this satellite. It is also catalogued as 2MASS J11181079+4802126 in Two-Micron All Sky Survey catalogue of infrared objects, and has been given the variable star designation KV Ursae Majoris.

The absolute magnitude of this star is −0.82. This object is an aging red giant star with a stellar classification of M0 III, having exhausted the supply of hydrogen at its core then cooled and expanded. At present it has around 61 times the radius of the Sun. It is a suspected variable star of unknown type, with a brightness that has been measured ranging from 4.94 down to 4.98.

Lois Slocum taught at Wellesley College with Leah Allen early in her career. She was a member of the astronomy department at Smith College from 1932 to 1943, and in 1944 joined the faculty at Wilson College. During World War II, she worked at the Radio Research Laboratory at Harvard. She was an active member of the American Astronomical Society (elected 1922) and the American Association of Variable Star Observers.

In the spectrum of this star, this high rate of spin is causing absorption lines to blend together because of the Doppler effect, making them more difficult to analyze. It is a periodically variable star that undergoes non-radial pulsations with a primary period of 1.1811 days and a secondary period of 0.1281 days. There is some disagreement about the mass of this star in the literature. Tetzlaff et al.

Having exhausted the supply of hydrogen at its core, the star has cooled and expanded. It now has 18 times the Sun's girth and is radiating 127 times the luminosity of the Sun at an effective temperature of 4,638 K. κ Lyrae is a red clump giant, which means it is on the horizontal branch and is generating energy through core helium fusion. It is a suspected small amplitude variable star.

V344 Carinae is a single star in the southern constellation of Carina. It has the Bayer designation f Carinae, while V344 Carinae is its variable star designation. This star has a blue-white hue and is visible to the naked eye with an apparent visual magnitude that fluctuates around 4.50. Historically, it was mentioned in the Almagest, suggesting that some time around 130 BCE it was brighter than its current magnitude.

However, subsequent examination in the ultraviolet band showed the silicon bands were as expected and it was determined the spectra is normal for a star of its type. There is no indication of variability in the star's spectrum. Observation during the Hipparcos mission showed no photometric variability down to a limit of ±0.003 magnitudes. For this reason, the star has been ruled out as a Beta Cephei type variable star.

R Lyrae near Vega R Lyrae is a 4th magnitude semiregular variable star in the constellation Lyra, approximately 350 light years away from Earth. It is a red giant star of the spectral type M5III, meaning it has a surface temperature of under 3,500 kelvins. It is much larger and brighter, yet cooler, than the Sun. In the near-infrared J band, it is brighter than the nearby Vega.

It is a variable star, considered an Orion variable, with occasional fading and other variability caused by obscuration from the surrounding dust. The apparent magnitude varies irregularly between 10.2 and 10.7. The properties of the star are calculated based on its maximum brightness, assumed to be the least obscured. The secondary is a T Tauri star, detected by distinctive spectral lines that could not be produced by the hotter primary star.

Eggleton and Tokovinin (2008) listed this as a suspected binary star system consisting of two roughly equal components. It appears as an ageing red giant with a stellar classification of M0III. This is a suspected semiregular variable star with a very small amplitude and a period of 40 days or more. Having exhausted the supply of hydrogen at its core, it has expanded to 44 times the Sun's radius.

It is considered an Oosterhoff type I cluster (OoI), despite having a relatively low metallicity. Indeed, it has the lowest metallicity of any OoI cluster known. There are 19 RR Lyrae variable star candidates and as many as 23 blue stragglers. A high proportion of the latter are concentrated near the dense core of the cluster, which is consistent with the idea that blue stragglers form through stellar mergers.

It is spinning rapidly with a projected rotational velocity of 215 km/s. Pi Aquarii is notable for having undergone a transition from a Be star (showing hydrogen emission lines) into an ordinary B-type star. It is classified as a Gamma Cassiopeiae type variable star and its brightness varies from magnitude +4.45 to +4.71; a range of 0.28. The dominant variability period, , is nearly the same as the orbital period.

Having exhausted the supply of hydrogen at its core, it has cooled and expanded until it now has around 99 times the girth of the Sun. It is a suspected variable star with a brightness that has been measured varying from magnitude 5.13 down to 5.20. The star is radiating 2,158 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 3,954 K.

SU Aurigae is a T Tauri-type variable star in the constellation Auriga. It is located about 500 light-years (150 parsecs) away in the Taurus-Auriga Star Forming Region. Its apparent magnitude is 9.30, which is dim enough that it cannot be seen with the unaided eye. SU Aurigae's spectral type of G2IIIne means that it is a G-type star with an effective temperature similar to the Sun.

BF Antliae, or HD 86301, is a variable star in the southern constellation of Antlia. It has a baseline apparent visual magnitude of 6.32, which indicates it lies near the lower limit of visibility for faint stars. The distance to BF Ant, as determined from its annual parallax shift of , is 473 light years. It is moving further away with a heliocentric radial velocity of +18 km/s.

A binary star system consists of two stars that orbit around their common centre of mass. The movements of both stars lie on a common orbital plane in space. When this plane is very closely aligned with the location of an observer, the stars can be seen to pass in front of each other. The result is a type of extrinsic variable star system called an eclipsing binary.

HR Carinae is a luminous blue variable star located in the constellation Carina. It is surrounded by a vast nebula of ejected nuclear-processed material because this star has a multiple shell expanding atmosphere. This star is among the most luminous stars in the Milky Way. It has very broad emission wings on the Balmer lines, reminiscent from the broad lines observed in the spectra of O and Wolf–Rayet stars.

Light curve for the Mira variable S Coronae Borealis over six years S Coronae Borealis (S CrB) is a Mira variable star in the constellation Corona Borealis. Its apparent magnitude varies between 5.8 and 14.1, with a period of 360 days—just under a year. Within the constellation, it lies to the west of Theta Coronae Borealis, and around 1 degree southeast of the eclipsing binary star U Coronae Borealis.

Hercules has no first or second magnitude stars. However, it does have several stars above magnitude 4. Alpha Herculis, traditionally called Rasalgethi, is a triple star system, partly resolvable in small amateur telescopes, 359 light-years from Earth. Its common name means "the kneeler's head". The primary is an irregular variable star; it is a bright giant with a minimum magnitude of 4 and a maximum magnitude of 3.

AC Andromedae (AC And) is a variable star in the constellation Andromeda. Its maximum apparent visual magnitude is 10.77, but can be seen fainter down to a magnitude of 11.9. The nature of AC Andromedae is still not determined. Its light curve shows clearly three radial pulsation modes, the fundamental one with a period of 0.71 days, and the first two overtones of 0.525 and 0.421 days, respectively.

S Vulpeculae is a star located in the constellation Vulpecula. A supergiant star, it is around 382 times the diameter of the Sun. S Vulpeculae was first suspected of varying in brightness in 1836 and this was confirmed by 1862. A pulsating variable that grows and shrinks as it changes in brightness, it has been variously classified as an RV Tauri variable, a semiregular variable star, or a Cepheid variable.

The two stars form an eclipsing binary system (variable star designation: V1488 Cyg) similar to Algol. The orbital plane of the two stars is nearly aligned with the line of sight from the Earth, so that the giant star eclipses the secondary component once per orbit. During an eclipse, emission lines can be seen in the spectrum of this system. These originate in the stellar wind escaping from the giant star.

Close to Gamma Corvi and visible in the same binocular field is R Corvi, a long period (Mira) variable star. It ranges in brightness from a magnitude of 6.7 to 14.4 with a period of approximately 317 days. TT Corvi is a semiregular variable red giant of spectral type M3III and apparent magnitude 6.48 around 923 light years distant. It is around 993 times as luminous as the Sun.

The head of the snake corresponds to the Āshleshā Nakshatra, the lunar zodiacal constellation in Indian astronomy. The name of Nakshatra (Ashlesha) became the proper name of Epsilon Hydrae since 1 June 2018 by IAU. Hydra is also home to several variable stars. R Hydrae is a Mira variable star 2000 light-years from Earth; it is one of the brightest Mira variables at its maximum of magnitude 3.5.

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.

She earned an MA in Astronomy from Radcliffe College, Harvard University, in 1928. She worked as a research assistant and astronomer at Harvard College Observatory from 1924 to 1954, and was at the Heat Research Laboratory, Special Weapons Group, Massachusetts Institute of Technology from 1943 to 1946. While working in Nantucket, she met Robert Newton Mayall, a member of the American Association of Variable Star Observers (AAVSO). They married in 1927.

9 Persei is a single variable star in the northern constellation Perseus, located around 4,300 light years away from the Sun. It has the Bayer designation i Persei; 9 Persei is the Flamsteed designation. This body is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of 5.17. It is moving closer to the Sun with a heliocentric radial velocity of −15.2 km/s.

RASNZ coordinates a number of sections (groups of people who share a common interest) including the Occultation, Education and Variable Star sections. The RASNZ holds an annual conference, generally hosted by one of the affiliated societies. The conference is open to non-members. A wide range of papers are presented during the conference and often symposiums related to the RASNZ's sections are held in conjunction with the conference.

Vizier catalog entry Vizier catalog entry Component A is also a suspected variable star, reported to vary from 4.57 to 4.77 in magnitude. It was reported as possibly variable in 1952 during a search for β CMa variables, but has not been seen to vary since. It was listed as one of the least variable stars based on Hipparcos photometry. On the 29 May 1983, 1 Vulpeculae occulted the asteroid Pallas.

64 Eridani is a single, yellow-white hued star in the constellation Eridanus having variable star designation S Eridani. It is faintly visible to the naked eye with an apparent visual magnitude of 4.77. The annual parallax shift is measured at , which equates to a distance of about . In addition to its proper motion, it is moving closer to the Sun with a radial velocity of around −9 km/s.

This is giving it an oblate shape with an equatorial bulge that is 5% larger than the polar radius. The axis of rotation is inclined by an angle of 45° to the line of sight from the Earth. Samus et al. (2017) classify it as a Be-type variable star that ranges from a peak visual magnitude of 5.13 down to 5.44 with a rotationally-modulated period of 2.63 days.

However, Gray and Garrison (1987) found a class of A0.5 IVnn, which would instead match an evolving subgiant star. It is a suspected variable star of unknown type. This object is 149 million years old with 2.23 times the mass of the Sun and about 2.5 times the Sun's radius. It is radiating 65 times the Sun's luminosity from its photosphere at an effective temperature of 9,972 K.

It lies half a degree away from S Persei, another red supergiant Double Cluster member. T Per is a semiregular variable star, whose brightness varies from magnitude 8.34 to 9.7 over a period of 2,430 days. Unlike many red supergiants, it does not appear to have a long secondary period. The Washington Double Star Catalog lists T Persei as having a 9th magnitude companion 0.1 arc-seconds away.

Gliese 1061 is a non-variable star that does not produce significant flares. Consequently, there is a greater probability that the exoplanet Gliese 1061 c still conserves its atmosphere, if it has one. It is an exoplanet warmer than Earth, with an equilibrium temperature of almost 2 K greater, so the average temperature on the surface could be around , provided the atmosphere is of similar composition to the Earth's.

The stellar spectrum displays an overabundance of heavier elements; particularly silicon and gallium. These abundances may be caused by the magnetic field of the star, which produces concentrations of the observed elements in the outer atmosphere. It is a α² Canum Venaticorum-type variable star, ranging in magnitude from 5.15 down to 5.22. These variations are likely due to large spots or rings on the side of the star being observed.

The AAVSO International Variable Star Index defines a LERI type of variation. λ Eri is classified as LERI + GCAS since it shows both short term periodic variations and longer timescale eruptive variation. It was one of the first stars where short-period variations were found. The line profile variability periods are 0.702d and 0.269d, with intermittently present periods of 0.6d and 0.75d. The photometric amplitude of the variation is 0.010 magnitude.

Beta Sextantis, Latinized from β Sextantis, is a variable star in the equatorial constellation of Sextans. With an apparent visual magnitude of 5.07, it is faintly visible to the naked eye on a dark night. According to the Bortle scale, it can be viewed from brighter lit suburban skies. The distance to this star, based upon an annual parallax shift of 8.06 mas, is around 400 light years.

14 Lacertae is a binary star system in the northern constellation Lacerta, located around 1,600 light years away. It has the variable star designation V360 Lacertae; 14 Lacertae is the Flamsteed designation. The system is barely visible to the naked eye in good seeing conditions, having a peak apparent visual magnitude of 5.91. It is moving closer to the Earth with a heliocentric radial velocity of −16 km/s.

This is a double-lined spectroscopic binary in a close, circular orbit with a period of 10.08 days and a separation of . The orbital inclination is . 14 Lac is a variable star system that, once per orbit, shows a primary minimum with a 0.07 magnitude decrease and a secondary minimum with a decrease of 0.02. The primary component is a Be star that is spinning rapidly at its critical velocity.

He started the program of observation of variable stars using this telescope. M K Vainu Bappu made variable star observations from here in the 1940s and 1950s. A spectrohelioscope and a blink comparator was added in the mid-1940s. It participated in Carte du Ciel between 1908 and 1944, an international astronomy observation program. It was assigned the co-ordinates from 17 to 23 degrees South between 1914 and 1929.

The primary component of the pair, κ Sco A, is a variable star of Beta Cephei type. It is undergoing radial pulsations with a dominant frequency of 4.99922 cycles per day, or 4.8 hours per cycle. There are overlapping secondary pulsation frequencies of about 4.85 and 5.69 cycles per day. This star has about 17 times the mass of the Sun and is nearly 7 times the Sun's radius.

Growing to tall by broad, it is a leafless succulent perennial with cactus-like toothed stems, and highly variable, star-shaped, off-white or yellow flowers strongly speckled with maroon, up to in diameter. The flowers may show regular (banded) markings, or irregular ones. They have five pointed or blunt lobes surrounding a central, pentagonal annulus (corona). The flowers may have a faint carrion smell to attract potential insect pollinators.

R Normae is a Mira variable star located near Eta Normae in the southern constellation of Norma. This is an intermediate-mass red giant star that is generating part of its energy through hydrogen fusion. Because this fusion is thought to be occurring under conditions of convection, it is generating an excess of lithium. The star ranges from magnitude 6.5 to 12.8 and has a relatively long period of 496 days.

The outer envelope of λ Velorum has an effective temperature of about 4,000 K, giving it the cool orange hue of a K-type star. It is an Lc- type, slow irregular variable star with its brightness varying between apparent magnitudes +2.14 to +2.30. λ Velorum is an evolved star that has exhausted the hydrogen in its core region. It has about seven times the mass of the Sun.

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.

It is twice as massive and 3.3 times as wide as our sun and 26 times more luminous. A line drawn between Alpha Hydri and Beta Centauri is bisected by the south celestial pole. In the southeastern corner of the constellation is Gamma Hydri, a red giant of spectral type M2III located 214 light-years from Earth. It is a semi-regular variable star, pulsating between magnitudes 3.26 and 3.33.

Richard D. Lines (April 21, 1916 - June 29, 1992) was an American amateur astronomer. He started as a deep-sky observer and photographer, but later specialized in photometry of variable stars. He was a member of the American Association of Variable Star Observers and International Amateur-Professional Photoelectric Photometry (I.A.P.P.P.). Together with his wife Helen Chambliss Lines, also a keen astronomer, he built a small observatory in Mayer, Arizona.

The earliest observations of CH Cygni were made in 1890 by Pickering and Wendel using wedge photometer, and was classified as a M6III variable star in 1924. In 1963 strong H I emissions were observed, indicating CH Cygni was likely in a symbiotic relationship with a white dwarf. Similar emissions were observed in 1965, 1967, 1977, 1992, and 1998. The system was briefly thought to contain a third star but this was later disproved.

It has around 18 times the mass of the Sun and 12 times the Sun's radius. This star is radiating about times the luminosity of the Sun from its outer envelope at an effective temperature of . This is a variable star of the Beta Cephei type, causing the apparent magnitude to vary between +2.86 and +2.94 with multiple periods of , , and 8.2 days. During each pulsation cycle, the temperature of the star varies by .

X Cancri is a variable star in the northern constellation of Cancer. It has a red hue and is visible to the naked eye at peak magnitude, fluctuating around an apparent visual magnitude of 6.28. The distance to this object is approximately 2,900 light years based on parallax measurements, but is drifting closer with a radial velocity of −5 km/s. It lies very close to the equinox and so is subject to lunar occultations.

This is an evolved, K-type giant star with a stellar classification of K3 III. It is a suspected optical variable star with a magnitude range of 5.42 to 5.46. At infrared wavelengths, it shows large amplitude variation with a period of 505 days. The star has expanded to about 37 times the Sun's radius and is radiating 301 times the solar luminosity from its photosphere at an effective temperature of 4,040 K.

BI Cygni (BI Cyg, IRC +40408, BD+36 4025) is a red supergiant in the constellation Cygnus. It is an irregular variable star with a maximum brightness of magnitude 8.4 and a minimum of magnitude 9.9. It is considered a member of the stellar Cygnus OB1 association, its distance is around 1,400 parsecs (4,500 light-years) of the Solar System. It is less than a degree south of another variable red supergiant, BC Cygni.

The system consists of a pair of binary stars separated by 66.6 arcseconds. The primary, component A, is a yellow-white F-type subgiant with an apparent magnitude of +4.25. It is classified as a Delta Scuti type variable star and its magnitude varies by 0.04 with a period of 0.1557 days. Its binary companion, component B, is also a F-type subgiant which is slightly dimmer, with a magnitude of +5.2.

BM Scorpii, is classed as a semiregular variable star, its brightness varying from magnitude +5.5 to magnitude +7.0. There are also eight candidate chemically peculiar stars. The cluster is located from the Galactic Center and is following an orbit through the Milky Way galaxy with a low eccentricity of 0.03 and an orbital period of 204.2 Myr. At present it is below the galactic plane, and it will cross the plane every 29.4 Myr.

Light curves can be periodic, as in the case of eclipsing binaries, Cepheid variables, other periodic variables, and transiting extrasolar planets, or aperiodic, like the light curve of a nova, a cataclysmic variable star, a supernova or a microlensing event or binary as observed during occultation events. The study of the light curve, together with other observations, can yield considerable information about the physical process that produces it or constrain the physical theories about it.

R Leonis is a red giant Mira-type variable star located approximately 300 light years away in the constellation Leo. The apparent magnitude of R Leonis varies between 4.31 and 11.65 with a period of 312 days. At maximum it can be seen with the naked eye, while at minimum a telescope of at least 7 cm is needed. The star's effective temperature is estimated 2,890 kelvins and radius spans , roughly Mars's orbital zone.

The central part of the cluster is framed by bright stars making up an "A"-shaped asterism. The upper tip of this asterism is HD 111904 (HR 4887, HIP 62894), a B9 supergiant and suspected variable star. It is the brightest member of the A asterism at magnitude 5.77. The brightest star in the region of the cluster is the variable DS Cru (HD 111613, HR 4876), which lies well beyond the A asterism.

Gamma Pictoris is an orange giant of spectral type K1III that has swollen to 1.4 times the diameter of the Sun. Shining with an apparent magnitude of 4.5, it lies 174 light-years distant from Earth. HD 42540, called 47 Pictoris by American astronomer Benjamin Apthorp Gould, is a slightly cooler orange giant, with a spectral type of K2.5III and average magnitude 5.04. It has also been suspected of being a variable star.

This object is an aging G-type giant star with a stellar classification of G6/8 III. Having exhausted the supply of hydrogen at its core, the star has cooled and expanded until now it has 11 times the girth of the Sun. It is a suspected variable star of unknown type. The star is radiating 71 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,967 K.

It is a slow irregular variable star with a possible period of 3,100 days. It is over 60,000 times the luminosity of the Sun, and it is 645 times larger than the Sun. It is a member of the Cas OB5 stellar association, together with the nearby red supergiant PZ Cassiopeiae. The initial mass of TZ Cassiopeiae has been estimated from its position relative to theoretical stellar evolutionary tracks to be around .

In 1990 he joined the Hungarian Astronomical Association and became the Co-ordinator of the Cometary Section the same year. In 1994 he became a member of the Executive Committee and in 1996 he was appointed secretary. In 1996 he also joined the American Association of Variable Star Observers (AAVSO). Krisztián Sárneczky has published a number of articles in the astronomy community, and has a large number of asteroid discoveries to his credit (see ).

Membership in the SBAS is open to anyone 10 years of age or older, but only those of at least 16 years of age may vote and hold office. Members of all ages may participate in society activities. The society currently has a membership of more than 80 people. Society members contribute to the hobby of amateur astronomy via articles in astronomy publications, variable star observing, asteroid occultations, Astronomical League observing programs, and outreach events.

This is an evolved K-type giant star on the horizontal branch, with a stellar classification of K0/1 III. It is a suspected variable star with a measured variation between 4.45 and 4.49 in visual magnitude. Pi6 Orionis has over four times the mass of the Sun and has expanded to around 88 times the Sun's radius. Over the course of its life span, the star has shed around solar masses.

Daniel Overbeek's serious interest in astronomy dates back to 1951, when he started observing occultations and variable stars. In 1958 he earned a B.Sc. degree in mathematics and astronomy from the University of South Africa. In his life he contributed 287,240 observations to the American Association of Variable Star Observers (AAVSO) International Database, becoming the most prolific AAVSO contributor. In 1998 he became the first amateur astronomer who detected supernova related gamma ray burst effects.

HD 179791 is suspected variable star in the equatorial constellation of Aquila. It is a challenge to see with the naked eye even under good viewing conditions, having an apparent visual magnitude of 6.48. The distance to HD 179791 can be estimated from its annual parallax shift of , which yields a value of 616 light years. It is moving further from the Earth with a heliocentric radial velocity of +16 km/s.

It has never been given a formal variable star designation, unlike L1 Puppis which is OU Puppis. L2 Puppis varies in apparent magnitude by about 2 magnitudes with a period of 140 days. The average brightness also varies slowly over several years so that the total range is given as magnitude 2.6 – 6.0. Since 1995 the average brightness has dropped so that the 140 day variations are now between about magnitude 6 and 8.

This object is an aging giant star with a stellar classification of K4+ III. A 1993 study found that it varied in brightness by 0.05 magnitude over 25 to 30 days. It is classified as a semiregular variable with a brightness that ranges from 4.21 to as low as 4.27, and has the variable star designation BN Lyncis. 31 Lyncis is 1.3 billion years old with almost double the mass of the Sun.

RT Aurigae (RT Aur, 48 Aurigae) is a yellow supergiant variable star in the constellation Auriga, about 1,500 light years from Earth. RT Aurigae is an F to G type Classical Cepheid variable which varies from magnitude +5.00 to +5.82 with a period of 3.728309 days. The variability was discovered in 1905. It was quickly recognised as a member of the class of Cepheid variables, but their nature was not understood at that time.

This is a suspected variable star of unknown type with a measured amplitude of 0.02 in visual magnitude. It is radiating 315 times the luminosity of the Sun from its photosphere at an effective temperature of 11,083 K, and is spinning with a projected rotational velocity of 65 km/s. The secondary companion is a magnitude 7.82 star at an angular separation of along a position angle of 34° from the primary, as of 2008.

At that distance, its brightness is diminished by 0.21 in magnitude from extinction caused by interstellar gas and dust. This is a suspected spectroscopic binary with an angular separation of between the two components. The visible component is an evolved giant star with a stellar classification of K1 III. It is a suspected variable star of unknown type, and is around 2.6 billion years old with 1.6 times the mass of the Sun.

S Apodis (HD 133444) is an R Coronae Borealis variable star located in the far southern constellation Apus. These are extremely hydrogen-deficient supergiants thought to have arisen as the result of the merger of two white dwarfs; fewer than 100 have been discovered as of 2012. Located around 13,000 light-years distant, it shines with a luminosity approximately 960 times that of the Sun and has a surface temperature of 3916 K.

14 Aurigae is a quintuple star system located 269 light years away from the Sun in the zodiac constellation of Auriga. It has the variable star designation KW Aurigae, whereas 14 Aurigae is the Flamsteed designation. It is visible to the naked eye as a faint, white-hued star with a combined apparent visual magnitude of 5.01. The system is moving closer to the Sun with a heliocentric radial velocity of −9 km/s.

It is a variable star of unknown type that ranges in magnitude from 5.03 down to 5.09. This star is an estimated 36 million years old with a projected rotational velocity of 8 km/s. It has 8 times the mass of the Sun and about 15 times the Sun's radius. 19 Aurigae is radiating 7,057 times the total luminosity of the Sun from its photosphere at an effective temperature of 8,300 K.

9 Andromedae, abbreviated 9 And by convention, is a variable binary star system in the northern constellation Andromeda. 9 Andromedae is the Flamsteed designation, while it bears the variable star designation AN Andromedae, or AN And. The maximum apparent visual magnitude of the system is 5.98, which places it near the lower limit of visibility to the human eye. Based upon an annual parallax shift of , it is located 460 light years from the Earth.

The nebula is most commonly referred to as LoTr 5, short for Longmore-Tritton 5. It was discovered in 1980 by A. J. Longmore and S. B. Tritton, who found the nebula on photographic plates taken at the UK Schmidt Telescope. The central star has a number of different names. It is often referred to by its Henry Draper Catalogue designation HD 112313, or by its variable star designation IN Comae Berenices.

The larger, primary star is designated component A, while the secondary, smaller star is labeled component B. Component A has about 27% of the Sun's mass and 35% of the Sun's radius. Component B has about 18% of the Sun's mass and 24% of the Sun's radius. The data is from the Vizier II/224 catalogue. Component B is a flare star and has been given the variable star designation "DO Cephei".

The 'e' suffix is used to mark the presence of emission lines, which indicates this is a Be star surrounded by a circumstellar disk of hot gas that was formed from material ejected from the star. Mu Centauri is a pulsating variable star that has multiple non-radial cycles with a primary period of 0.503 days. Three other pulsation cycles have a similar period, while two have a shorter interval of about 0.28 days.

It is a Beta Cephei type variable star with a brightness that periodically varies from magnitude +3.38 to +3.41 over an interval of 0.17 days. The tidal interaction with the secondary component has turned it into a rotating ellipsoidal variable. This star system is a proper motion member of the Upper-Centaurus Lupus sub-group in the Scorpius- Centaurus OB association, the nearest such association of co-moving massive stars to the Sun.

The star is a member of the HD 1614 supercluster. This is an evolved red giant star with a stellar classification of M5 III. It is classified as a semiregular variable star and its brightness varies from magnitude +4.16 to +4.26 with a period of 12.57 days. The star has around 70 times the Sun's radius and is radiating 72 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,398 K.

A flare star is a variable star that can undergo unpredictable dramatic increases in brightness for a few minutes. It is believed that the flares on flare stars are analogous to solar flares in that they are due to the magnetic energy stored in the stars' atmospheres. The brightness increase is across the spectrum, from X rays to radio waves. The first known flare stars (V1396 Cygni and AT Microscopii) were discovered in 1924.

T Andromedae (T And) is a variable star of the Mira type in the constellation Andromeda. Like all the stars of this kind, T And is a cool asymptotic giant branch star of spectral type M4e-M7.5e, and his variability occurs periodically, with the period calculated at 281 days. The peak luminosity, however, is different every variability cycle, but can reach a peak magnitude mv=7.70.General Catalogue of Variable Stars, s.v.

Zeta Andromedae (Zeta And, ζ Andromedae, ζ And) is a star system in the constellation Andromeda. It is approximately 189 light years from Earth. Zeta Andromedae is a spectroscopic binary whose primary is classified as an orange K-type giant with a mean apparent magnitude of +4.08. In addition to brightness variation due to the ellipsoidal shape of the giant primary star, the system is also an RS Canum Venaticorum type variable star.

The main period also varies over a period of decades. It has around 90% the mass of the Sun and an average effective (surface) temperature of around 5000 K. It is around 10,000 times as luminous as the Sun. Measurement of its parallax by the Gaia satellite yields a distance of around 8,100 light-years. Variable star observer David Levy recommends that amateur observers monitor it once a week to observe changes in brightness.

W Hydrae is a Mira-type variable star in the constellation Hydra. The star is nearly located within the Solar neighborhood, between 75 and 120 parsecs, likely at 375 light years from the Sun. It has a visual apparent magnitude range of 5.6 to 10. In the near-infrared J band it has a magnitude of -1.7, is the 7th brightest star in the night sky, and is even brighter than Sirius.

W Crucis is a single-lined eclipsing variable star system in the constellation Crux. It has a spectral class of F8/G1Ia/abe indicating a yellow supergiant with emission lines in its spectrum. W Crucis varies in brightness between magnitude 8.18 and 9.01 over a period of 198.5 days. Its light curve has been observed to be asymmetric with subsequent maxima differing in height, which is described as the so-called O'Connell effect.

The primary is a giant star with a stellar classification of . It is a Mercury- Manganese star, showing a surfeit of these elements in the spectrum. With five times the Sun's mass, this star is radiating 1,035 times as much luminosity from its outer atmosphere at an effective temperature of 12,593 K. This heat gives it the blue-white hue of a B-type star. The companion may be a variable star.

BB Phoenicis is a variable star in the constellation of Phoenix. It has an average visual apparent magnitude of 6.17, being visible to the naked eye with excellent viewing conditions. From parallax measurements by the Gaia spacecraft, it is located at a distance of from Earth. Its absolute magnitude is calculated at 0.6. BB Phoenicis is a Delta Scuti variable, and shows stellar pulsations that cause brightness variations with an amplitude of 0.04 magnitudes.

He observed it in the southern sky while working from an observatory at the Cape of Good Hope. In the past Lacaille 8760 has been classified anywhere from spectral class K7 down to M2. In 1979 the Irish astronomer Patrick Byrne discovered that it is a flare star, and it was given the variable star designation AX Microscopii. As a flare star it is relatively quiet, only erupting on average less than once per day.

T Tauri is a variable star in the constellation Taurus, the prototype of the T Tauri stars. It was discovered in October 1852 by John Russell Hind. T Tauri appears from Earth amongst the Hyades cluster, not far from ε Tauri; but it is actually 420 light years behind it and was not formed with the rest of them. Faint nebulosity around T Tauri is a Herbig–Haro object called Burnham's Nebula or HH 255.

One particularly interesting variable in Aries is SX Arietis, a rotating variable star considered to be the prototype of its class, helium variable stars. SX Arietis stars have very prominent emission lines of Helium I and Silicon III. They are normally main-sequence B0p—B9p stars, and their variations are not usually visible to the naked eye. Therefore, they are observed photometrically, usually having periods that fit in the course of one night.

CE Cam and the surrounding nebulosity at infrared wavelengths (Credit: NASA/JPL-Caltech/UCLA) HD 21389 is a supergiant variable star in reflection nebula VdB 15, in the constellation Camelopardalis. It is part of the Camelopardalis OB1 association. The near-identical member CS Camelopardalis lies half a degree to the north. Since 1943, the spectrum of CE Cam has served as one of the stable anchor points by which other stars are classified.

IC 405 (also known as the Flaming Star Nebula, SH 2-229, or Caldwell 31) is an emission and reflection nebula in the constellation Auriga, surrounding the bluish star AE Aurigae. It shines at magnitude +6.0. Its celestial coordinates are RA dec . It surrounds the irregular variable star AE Aurigae and is located near the emission nebula IC 410, the open clusters M38 and M36, and the K-class star Iota Aurigae.

The brightest of the five red supergiants is the exceptionally cool MY Cephei. It has a spectral type of M7.5 which is one of the latest spectral types of any supergiant, although analysis is made difficult by the lack of comparable standard stars. It is estimated to have an effective temperature of and a bolometric luminosity more than . MY Cephei is a semiregular variable star with a brightness range of magnitude 14.4 - 15.3.

The Clinton B. Ford Observatory (Wrightwood) (Observatory Code 674) is an astronomical observatory that is associated historically with the American Association of Variable Star Observers (AAVSO). The observatory is located near the border of the Angeles National Forest and the San Bernardino National Forest near Wrightwood, California (United States). It was founded by the late astronomer Clinton B. Ford. In 2012, the Clinton B. Ford Observatory was donated to the Los Angeles Astronomical Society (LAAS).

SV Vulpeculae is a Classical Cepheid (δ Cepheid) variable star in the constellation Vulpecula. It is a supergiant at a distance of 8,700 light years. SV Vulpeculae is a δ Cepheid variable whose visual apparent magnitude ranges from 6.72 to 7.79 over 45.0121 days. The light curve is highly asymmetric, with the rise from minimum to maximum taking more less than a third of the time for the fall from maximum to minimum.

SW Andromedae is a variable star in the constellation of Andromeda. It is classified as an RR Lyrae star, and varies from an apparent magnitude of 10.09 at minimum brightness to a magnitude of 9.14 at maximum brightness with a period of 0.44226 days.SW 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 2014-07-02.

It is rotating rapidly with a projected rotational velocity of . The interferometry-measured angular diameter of this star is , which, at its estimated distance, equates to a physical radius of about six times the radius of the Sun. Observations by German astronomer Ernst Zinner in 1929 gave indications that this may be a variable star. It was listed in the New Catalogue of Suspected Variable Stars (1981) with a magnitude range of 3.74 to 3.81.

This is an aging bright giant/supergiant star with a stellar classification of K2 Ib-II. It is a suspected variable star of unknown type, with a brightness that has been measured ranging from 4.83 down to 4.87. HD 115211 is an estimated 40 million years old with 7.1 times the mass of the Sun. With the supply of hydrogen exhausted at its core, it has expanded to 123 times the Sun's radius.

R Andromedae (R And) is a Mira-type variable star in the constellation Andromeda. Its spectral class is type S because it shows absorption bands of zirconium monoxide (ZrO) in its spectrum. It was among the stars found by Paul Merrill to show absorption lines of the unstable element technetium, establishing that nucleosynthesis must be occurring in stars. The SH molecule was found for the first time outside earth in the atmosphere of this star.

Published spectral types for the star vary somewhat from C54 to C64, or N6 under an older system of classification. The subscript 4 refers to the strength of the molecular carbon bands in the spectrum, an indicator of the relatively abundances of carbon in the atmosphere. V Aquilae is a variable star of type SRb. It has a published period of 400 days, but other periods are found including 350 days and 2,270 days.

This is an aging giant star with a stellar classification of . The suffix notation indicates abnormally weak lines of carbyne. Having exhausted the hydrogen at its core, the star evolved away from the main sequence by expanding to 11 times the Sun's radius. The star is radiating 65.6 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,953 K. It is a suspected variable star of unknown type.

Gamma Cassiopeiae, Latinized from γ Cassiopeiae, is a star at the center of the distinctive "W" asterism in the northern circumpolar constellation of Cassiopeia. Although it is a fairly bright star with an apparent visual magnitude that varies from 1.6 to 3.0, it has no traditional Arabic or Latin name. It sometimes goes by the informal name Navi. Gamma Cassiopeiae is a Be star, a variable star, and a binary star system.

Beta Andromedae is a red giant with a stellar classification of M0 III. Since 1943 the spectrum of this star has been one of the stable anchor points by which other stars are classified. It is suspected of being a semiregular variable star whose apparent visual magnitude varies from +2.01 to +2.10. At this stage of the star's evolution, the outer envelope has expanded to around 100 times the size of the Sun.

V Coronae Australis (V CrA) is a R Coronae Borealis variable star in the constellation Corona Australis. These are extremely hydrogen-deficient supergiants thought to have arisen as the result of the merger of two white dwarfs; fewer than 100 have been discovered as of 2012. V Coronae Australis dimmed in brightness from 1994 to 1998. It has around 60% the mass of the Sun and an effective (surface) temperature of around 6250 K.

BK Camelopardalis is a solitary variable star in the northern circumpolar constellation of Camelopardalis, near the constellation border with Cassiopeia. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude that fluctuates around 4.74. The star is located approximately 540 light years away from the Sun based on parallax. It is a proposed member of the Cassiopeia–Taurus group of co-moving stars.

It is also an irregular variable star with a range of less than a tenth of a magnitude. The orbital parameters can be used to derive the masses of the two stars, giving and . The distance to S Monocerotis and NGC 2264 has been derived in various ways, including dynamical parallax and isochrone fitting. These consistently give estimates of 700 - 900 parsecs, although this is double the likely distance derived from the Hipparcos parallax measurements.

12 Vulpeculae is a star in the northern constellation of Vulpecula, located approximately 630 light years away based on parallax. It has the variable star designation V395 Vul; 12 Vulpeculae is the Flamsteed designation. This object is visible to the naked eye as a faint, blue-white hued star with a baseline apparent visual magnitude of 4.96. It is moving closer to the Earth with a heliocentric radial velocity of -25 km/s.

Tau4 Serpentis, Latinized from τ4 Serpentis, is a M-type bright giant star in the constellation of Serpens, approximately 520 light-years from the Earth. It is classified as a semiregular late-type variable star, and its magnitude varies between +5.89 and +7.07 with a period of approximately 100 days. τ4 is unique among the stars with the Bayer designation τ Serpentis as being the only one with no HR catalog number.

One of the most observed Be stars of the Southern Hemisphere, Omega Canis Majoris is classified as a Gamma Cassiopeiae-type variable star. Both the luminosity and the radial velocity vary with a primary cyclical period of 1.372 days. The variation in brightness, ranging from magnitude +3.60 to +4.18, shows changes over time, which suggests there are two overlapping periods of 1.37 and 1.49 days. The star also undergoes transient periodicities following outbursts.

This is a B-type supergiant star with a stellar classification of B1 Ib. It is classified as a Beta Cephei type variable star and its brightness varies from magnitude +4.79 down to +4.84 with a period of . The star has 12.8 times the mass of the Sun and 6.8 times the Sun's radius. It is radiating 20,000 times the luminosity of the Sun from its photosphere at an effective temperature of 26,100 K.

The New Catalogue of Suspected Variable Stars (NSV) is a star catalogue containing 14,811 stars which, although suspected to be variable, were not given variable star designations prior to 1980. It was published in 1982.New Catalogue of Suspected Variable Stars: The Improved Version, explanatory file, B. V. Kukarkin et al., Institute of Astronomy of Russian Academy of Sciences and Sternberg State Astronomical Institute of the Moscow State University, accessed on line October 2, 2008.

It is a variable star that ranges in brightness from 5.34 down to 5.58. Samus et al. (2017) have it categorized as an α2 Canum Venaticorum variable with a period of 2.7347 days, while Adelman and Sutton (2007) found a period of 2.73501 days. The star has three times the mass and radius of the Sun and is radiating 110 times the Sun's luminosity from its photosphere at an effective temperature of 11,561 K.

Alpha Circini (α Cir, α Circini) is a variable star in the faint, southern, circumpolar constellation of Circinus. At an apparent visual magnitude of 3.19, it is the brightest star in the constellation and can be readily seen with the naked eye from the southern hemisphere. Parallax measurements of this star yield an estimated distance of from the Earth. This star belongs to a class of variables known as rapidly oscillating Ap stars.

It is a semiregular variable star of subtype SRb, ranging in magnitude from 4.28 down to 4.36. The star has pulsation periods of 18.8 and 45.5 days, each with an amplitude of 0.019 in magnitude. With the hydrogen at its core exhausted, the star has expanded to around 69 times the Sun's radius and it is radiating 1,021 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 3,915 K.

12 Comae Berenices is a binary star system in the northern constellation of Coma Berenices. It is the brightest member of the Coma Cluster and is visible to the naked eye with an apparent visual magnitude of 4.80. Although listed as a suspected variable star, there is no photometric evidence of it being variable in luminosity. However, the radial velocity was found to be variable, as announced by W. W. Campbell in 1910.

The companion has been identified from a high excitation component in the spectrum and from radial velocity variations, but the orbit is unknown. U Lacertae is a variable star classified as a semiregular variable. The periodicity is uncertain but a main period of 150 days and a long secondary period of 550 – 690 days have been suggested. A study of Hipparcos satellite photometry found an amplitude of 0.77 magnitudes and found no periodicity.

These in turn orbit the third star once every 145 days. The fourth star is a F star that orbits the other three stars in a roughly fifty-year period. The mean combined apparent magnitude of the system is +3.73, but because the stars eclipse one another during their orbits, it is classified as a variable star, and its brightness varies from magnitude +3.70 to +3.79. Xi Tauri is approximately 210 light years from Earth.

SX Arietis variables are a class of variable stars. They are generally B-type main sequence stars of spectral types B0p to B9p— high-temperature analogues of Alpha2 Canum Venaticorum variables—and exhibit strong magnetic fields and intense He I and Si III spectral lines. They have brightness fluctuations of approximately 0.1 magnitudes with periods of about one day. The prototype of this class is 56 Arietis, which bears the variable star designation SX Arietis.

In 1865, Julius Schmidt first reported that η Geminorum was a variable star. The light variations were described by Schmidt and other observers as having long maxima of constant brightness, minima of greatly varying size and shape, and a period around 231 days. The star was classified as both a semiregular variable and an eclipsing variable. The eclipse period has been set at about eight years, corresponding to the orbit of an unseen companion.

Hyades, with ρ Tau appearing blue left of centre Rho Tauri (ρ Tau, ρ Tauri) is a star in the constellation Taurus and a member of the Hyades star cluster. Rho Tauri is a white A-type main sequence dwarf with a mean apparent magnitude of +4.66. It is approximately 158 light years from Earth. Classified as a Delta Scuti type variable star, its brightness varies by 0.010 magnitudes over a period of 1.61 hours.

It has an estimated mass loss rate of per year and has been once described as a cool hypergiant. It is surrounded by a dozen early-type stars and a circumstellar nebula which extends . HD 143183 is catalogued with the variable star designation V558 Normae as its brightness varies irregularly between apparent magnitudes 7.3 and 8.6. It is possible that HD 143183 is a spectroscopic binary with an OB+ companion but this is considered doubtful.

MM/DD/YY format χ Cygni shows one of the largest variations in apparent magnitude of any pulsating variable star. The observed extremes are 3.3 and 14.2 respectively, a variation of more than 10,000-fold in brightness. The mean maximum brightness is about magnitude 4.8, and the mean minimum is around magnitude 13.4. The shape of the light curve is fairly consistent from cycle to cycle, with the rise being steeper than the fall.

Castor C is a variable star, classified as a BY Draconis type. BY Draconis variables are cool dwarf stars which vary as they rotate due to starspots or other variations in their photospheres. The two red dwarfs of Castor C are almost identical, with masses around and luminosities less than 10% of the Sun. All the red dwarfs in the Castor system have emissions lines in their spectra, and all are flare stars.

HD 4778, also known as HR 234 and GO Andromedae, is a variable star in the constellation Andromeda. Its magnitude varies by 0.04 magnitudes from the median of 6.12 with a period of approximately 2.55 days. The star is located 350 light years away, as determined from its annual parallax shift of . This is an Ap star with a stellar classification of A3VpSiSrCrEuKsn, showing chemical peculiarities in its spectrum from strontium, chromium, and europium.

TW Horologii is a variable star in the southern constellation of Horologium, near the eastern constellation border with Reticulum. It has a ruddy hue and is dimly visible to the naked eye with an apparent visual magnitude that ranges from 5.52 down to 5.95. Based on parallax measurements, it is located at a distance of approximately 1,370 light years from the Sun. It is drifting further away with a radial velocity of +14 km/s.

HD 151967 is suspected variable star in the southern constellation of Ara. It is a sixth magnitude star, which means it is just visible to the naked eye in dark skies. Parallax measurements place it at a distance of approximately 710 light years from the Earth. This is a red giant with a stellar classification of M1III; it has expanded to 53 times the radius of the Sun and radiates 637 times the Sun's luminosity.

MACHO 176.18833.411 (OGLE BLG-RRLYR-10353) is an RR Lyrae variable star located in the galactic bulge of our Milky Way Galaxy. However, it is not a galactic bulge star, it is a galactic halo star, which is on the part of its elliptical orbit that brings it within the bulge before returning to the outer parts of the galaxy, the halo. The star is currently located about from the Galactic Center.

16 Lacertae is a triple star system in the northern constellation of Lacerta, located about 1,580 light years from the Sun. It has the variable star designation EN Lacertae; 16 Lacertae is the Flamsteed designation. This system is visible to the naked eye as a faint blue-white hued star with a maximum apparent visual magnitude of +5.587. It is moving closer to the Earth with a heliocentric radial velocity of −12 km/s.

This component is a Beta Cephei variable star with three dominant pulsation modes having frequencies of around six per day. It has a stellar classification of B2 IV, matching a B-type subgiant star with 9.5 times the mass of the Sun and 5.6 times the Sun's radius. The unseen secondary is an F-type star of class F6–7. The tertiary component is a magnitude 11.4 star with a class of F0.

RU Andromedae is a variable star in the constellation of Andromeda. It is classified as a semiregular variable pulsating giant star, and varies from an apparent visual magnitude of 14.5 at minimum brightness to a magnitude of 9.9 at maximum brightness, with a period of approximately 238.3 days.RU 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 2009-06-30.

RV Andromedae is a variable star in the constellation of Andromeda. It is classified as a semiregular variable pulsating giant star, and varies from an apparent visual magnitude of 11.5 at minimum brightness to a magnitude of 9.0 at maximum brightness, with a period of approximately 168.9 days.RV 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 2009-06-30.

This object is an M-type red giant, currently on the asymptotic giant branch, with a stellar classification of M1 III. It is an SRB-type semiregular variable star with its brightness varying by 0.0125 in magnitude. These variations have four periods lasting 11.1, 12.3, 16.8, and 23.7 days. This star has about 1.6 times the mass of the sun, but it has expanded to 54 times the Sun's radius and shines 631 times as brightly as the Sun.

This has allowed for the discovery of many new variable stars, often of very small amplitudes. Multiple period-luminosity relationships have been discovered, grouped into regions with ridges of closely spaced parallel relationships. Some of these correspond to the known Miras and semi-regulars, but an additional class of variable star has been defined: OGLE Small Amplitude Red Giants or OSARGs. OSARGs have amplitudes of a few thousandths of a magnitude and semi-regular periods of 10 – 100 days.

The spectrum showed emission lines of Fe XIII, which is heavily ionized iron that has been stripped of twelve of its electrons. The strength of this line can vary over a time period of several hours, which may be evidence of microflare heating. Wolf 359 is classified as a UV Ceti-type flare star, which is a star that undergoes brief, energetic increases in luminosity because of magnetic activity in the photosphere. Its variable star designation is CN Leonis.

The name Gliese 581 refers to the catalog number from the 1957 survey Gliese Catalogue of Nearby Stars of 965 stars located within 20 parsecs of the Earth. Other names of this star include BD-07° 4003 (BD catalogue, first known publication) and HO Librae (variable star designation). It does not have an individual name such as Sirius or Procyon. The star is a red dwarf with spectral type M3V, located 20.4 light-years away from Earth.

The MS index, not to be confused with an MS spectral class, indicates the strength of the SiC2 bands on a scale of one to seven. These bands are thought to be very sensitive to temperature. This is a semiregular variable star of subtype SRb that ranges in brightness from visual magnitude 5.52 down to 7.5 with a period of 193 days. Fourier analysis has shown that the star also pulsates with periods of 350 and 1,870 days.

The nebula has been identified on images taken by Evered Kreimer in October 1966, but not in various other images taken between 1951 and 1991. The nebula appears therefore to be very variable in luminosity, and is a reflection nebula illuminated by a variable star of some kind, or with the star's light being variably obscured for some reason.McNeil's Nebula near M78. The nebula was not observed after 2004 until 2008, when it reappeared once more.

Psi Leonis is an evolved red giant star with a stellar classification of M2 IIIab. It shines with a luminosity over 900 times that of the Sun from a relatively cool outer atmosphere that has an effective temperature of 3,756. It is a suspected variable star with a measured brightness variation of 0m.018. Psi Leonis has a magnitude 11.63 visual companion at an angular separation of 281.60 arcseconds along a position angle of 139°, as of 2000.

Since then, it has become one of the best-studied globular clusters. Identification of the cluster's unusually large variable star population was begun in 1913 by American astronomer Solon Irving Bailey and new variable members continue to be identified up through 2004. Many amateur astronomers consider it one of the finest northern globular clusters, following only Messier 13. M3 has an apparent magnitude of 6.2, making it a difficult naked eye target even with dark conditions.

Omicron¹ Eridani is an evolved F-type giant star with a stellar classification of F0 III. It is a Delta Scuti variable star that undergoes non-radial pulsations, with a variation of just 0.03 magnitude over a period of 0.0747 days. The star is spinning rapidly with a projected rotational velocity of 108.1 km/s and a rotation period of less than around 1.9 days. This is creating an equatorial bulge that is 11% wider than the polar radius.

It has a maximum magnitude of 5.10 and a minimum magnitude 6.83; its period of 131 days. It is a red giant ranging between spectral types M4e-M6e(Tc:)III, NML Cygni is a red hypergiant semi- regular variable star located at 5,300 light-years away from Earth. It is one of largest stars currently known in the galaxy with a radius exceeding 1,000 solar radii. Its magnitude is around 16.6, its period is about 940 days.

The measured angular diameter, after correction for limb darkening, is . At the estimated distance of the star, this yields a physical size of about 67 times the radius of the Sun. It is a suspected variable star, with an amplitude of 0.01 magnitude. The star radiates 864 times the solar luminosity from its outer atmosphere with an effective temperature of 4,053 K. In the next 7500 years, the south Celestial pole will pass close to this stars (4200 CE).

KK Andromedae, also known as HD 9531, is a variable star in the northern constellation of Andromeda. It has an apparent visual magnitude of 5.90, which places it near the lower limit of visibility to the naked eye even under good viewing conditions. An Alpha2 Canum Venaticorum variable, it varies in brightness by 0.012 magnitude every 0.66 days. Based upon an annual parallax shift of as seen from Earth, it is located around 437 light years from the Sun.

RT Carinae, also known as CD-58 3538, is a variable star in the Carina Nebula in the constellation Carina. It has a mean apparent magnitude of +8.55. RT Carinae is a red supergiant with a spectral type of M2+ Iab and has a temperature of 3,660 K. With a diameter 861 times that of the Sun, it is one of the largest stars known. The luminosity is estimated to be 120,000 times more luminous than the Sun.

It is close to the open cluster Trumpler 15, but is not thought to be a member. It appears to be surrounded by a dusty nebula, possibly material ejected from the star itself. It is catalogued as an irregular variable star, but a number of possible pulsation periods have been detected. Analysis from observations over 40 years give variations with periods of 201 and 448 days, with other studies suggesting periods of 100 and 1,400 days.

53 Persei is a single variable star in the northern constellation of Perseus. It has the Bayer designation d Persei, while 53 Persei is the Flamsteed designation. The star is visible to the naked eye as a faint, blue-white hued point of light with an apparent visual magnitude of 4.80. It is located approximately 480 light years away from the Sun, as determined from parallax, and is drifting further away with a radial velocity of +7.3 km/s.

Krisztián Sárneczky (born 6 November 1974 in Budapest) is a Hungarian teacher of geographyThe Konkoly Observatory personnel and prolific discoverer of minor planets and supernovae, researching at Konkoly Observatory in Budapest, Hungary. He is a board member of the Hungarian Astronomical Association (HAA)Introducing the Hungarian Astronomical Association and member of the American Association of Variable Star Observers, leader of the Comet Section of the HAA, and is a contributor in the editorial work of Hungarian Astronomical Almanach.

HD 202259 is a suspected variable star in the equatorial constellation of Aquarius. With an apparent magnitude of 6.39, according to the Bortle scale it is faintly visible to the naked eye from dark rural skies. It has a stellar classification of M1 III, and is a red giant located along the asymptotic giant branch of the HR diagram. Located about 900 light years away, its radial velocity of −123.5 km/s indicates this is a high-velocity star.

The star has a stellar classification of B8 III, matching a B-type giant. Absorption lines in the spectrum are displaying central quasi-emission peaks, indicating this is a Be shell star with a circumstellar disk of heated gas that is being seen edge- on. ν Puppis is a candidate variable star showing an amplitude of 0.0117 magnitude with a frequency of 0.15292 per day. It is spinning rapidly with a projected rotational velocity of 225 km/s.

GX Velorum is a solitary variable star in the southern constellation of Vela. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude that fluctuates around 4.99. Based upon parallax measurements, it is located approximately 4,200 light years distant from the Sun, and is drifting further away with a radial velocity of +28 km/s. It may be a member of the Vela OB1 association of co-moving stars.

HD 147513 is suspected of being a variable star.NSV 7680 -- Variable Star - SIMBAD entry HD 147513 is a member of the Ursa Major moving group that share a common proper motion through space. It has a nearby co-moving companion: a DA-class white dwarf located some 5,360 AU distant, where an AU is the average separation of the Earth from the Sun. At one time the pair may have been members of a multiple star system.

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.

These are designated Aa and Ab (although confusingly they may also be labeled as A and Aa, respectively). The primary is classified as an Alpha2 Canum Venaticorum-type variable star and the brightness of the system varies from magnitude +4.45 to +4.53 with a period of 1.74 days, because of its magnetic field. The fainter companion is a G-type star with a mass of only . The orbital period of the system is about 50 years.

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.

29 Aquarii is a binary star system located around 590 light years away from the Sun in the equatorial constellation of Aquarius. 29 Aquarii is the Flamsteed designation; the system also bears the variable star designation DX Aquarii. It is a challenge to view with the naked eye, appearing as a dim star with a combined apparent visual magnitude of 6.39. The system is moving further from the Earth with a heliocentric radial velocity of about +15 km/s.

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.

108 Aquarii (abbreviated 108 Aqr) is a star in the equatorial constellation of Aquarius. 108 Aquarii is the Flamsteed designation, although it also bears the Bayer designation i3 Aquarii and the variable star designation ET Aquarii. It has an apparent visual magnitude of 5.194 and can be seen with the naked eye under suitably dark skies. Based upon an annual parallax shift of 10.23 (with a 3% margin of error), the distance to this star is .

This is an aging giant star with a stellar classification of K1.5III-IIIb CN-1, where the suffix notation indicates an underabundance of cyanogen in the spectrum. Having exhausted the supply of hydrogen at its core, this star cooled and expanded off the main sequence. At present it has 25 times the radius of the Sun. HD 40657 is a suspected variable star with a brightness that has been measured ranging from magnitude 4.54 down to 4.58.

The third component is 5.5 magnitude star with a stellar classification of B5. Its angular separation from the binary pair is 0.15 arcseconds. This system is a proper motion member of the Upper Scorpius sub-group in the Scorpius-Centaurus OB association, the nearest such co-moving association of massive stars to the Sun. The primary component of this system is a variable star of the Beta Cephei type with a period of just 3h 22m.

The star has a peculiar velocity of relative to its neighbors, and may be a runaway star. This object is a bright giant star with a stellar classification of K2-IIb. It is a suspected variable star of unknown type with a brightness that has been measured varying from 4.73 down to 4.78. The star is about 61 million years old with 6.4 times the mass of the Sun and is spinning with a projected rotational velocity of 3.5.

It has an orbital period of about 10 years and an eccentricity of about 0.44. It is also a variable star, with its brightness changing between a maximum of magnitude 3.75 and a minimum of 3.83 in an unpredictable way. Delta Sagittae is moving through the Galaxy at a speed of 9.8 km/s relative to the Sun. Its projected Galactic orbit carries it between 23,800 and 35,300 light years from the center of the Galaxy.

Nu Fornacis, Latinized from ν Fornacis, is a single, variable star in the southern constellation of Fornax. It is blue-white in hue and faintly visible to the naked eye with an apparent visual magnitude that fluctuates around 4.69. This body is located approximately 370 light years distant from the Sun based on parallax, and is drifting further away with a radial velocity of +18.5 km/s. It is a candidate member of the Pisces-Eridanus stellar stream.

The timing of the light variations of T Antliae show a small scatter which can be fitted to a sine curve. This has been proposed to be due to light travel time caused by orbital movement of the variable star. This is based on somewhat uncertain data from old photograph records, and there is no confirmation of a companion. A compatible orbit would take 42.4 years to complete, with a semimajor axis around 10.8 Astronomical Units.

AU Microscopii (AU Mic) is a small star located away - about 8 times as far as the closest star after the Sun. The apparent visual magnitude of AU Microscopii is 8.73, which is too dim to be seen with the naked eye. It was given this designation because it is in the southern constellation Microscopium and is a variable star. Like β Pictoris, AU Microscopii has a circumstellar disk of dust known as a debris disk.

V4998 Sagittarii is an extremely luminous blue variable star (LBV) in the constellation of Sagittarius. Located some 25,000 light years away, the star is positioned ~7 pc (~23 ly) away from a starburst cluster known as the Quintuplet cluster. It has an ejection nebula measuring over 0.8 pc in diameter, formed 5000-10,000 years ago through large eruptions. The star has a large mass comparable to the Pistol star and a luminosity of ~4,000,000 times the Sun ().

NR Vulpeculae is a red supergiant and irregular variable star in the constellation Vulpecula. It has an effective temperature around 4,000 K, a radius of 553 times larger than the sun, which means that if it were in the place of the Sun, its surface would reach beyond Mars's orbit. Consequently, NR Vulpeculae is also a luminous star, radiating 70,000 times as much energy as the sun. It is considered a likely member of the Vulpecula OB1 stellar association.

T Carinae is a star in the southern constellation of Carina. Although given a variable star designation, it is now thought to be constant; the identifier HD 94776 from the Henry Draper catalogue may be used instead. It has an orange hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.93. The distance to this object is approximately 285 light years based on parallax, and it has an absolute magnitude of 1.08.

V382 Carinae The radial velocity of V382 Carinae has long been known to be variable, but variations in its brightness were unclear. Brightness variations were detected by some observers, but others found it to be constant. It was formally named as a variable star in 1981, listed in the General Catalogue of Variable Stars as a possible δ Cephei variable. It has been described as a pseudo-Cepheid, a supergiant with pulsations similar to a Cepheid but less regular.

V448 Carinae is a single star in the constellation Carina. It has the Bayer designation O Carinae, while V448 Carinae is the variable star designation. This object has an orange hue and is dimly visible to the naked eye with an apparent visual magnitude that fluctuates around 5.60. It is located at a distance of approximately 680 light years from the Sun based on parallax, and is drifting further away with a radial velocity of around +26 km/s.

Intense study of large numbers of stars suggest that 6.7% of stars with temperatures between and show rapid small-amplitude pulsations but are not members of other variable star classes. These are potentially Maia variables. Maia is surrounded by the Maia Nebula (also known as NGC 1432), a reflection nebula that is one of the brightest patches of nebulosity within the Pleiades star cluster. It is the only member of the New General Catalogue discovered photographically.

The star has a relatively high proper motion, traversing the celestial sphere at the rate of 0.195 arc seconds per annum. This is an aging giant star with a stellar classification of K4.5 III. It displays an enhanced abundance of elements generated through the alpha process, and, in particular, has a strong enhancement of silicon. 29 Herculis is a suspected variable star of unknown type, and has been measured ranging in visual magnitude from 4.82 down to 4.85.

It has slightly more mass and a slightly larger radius than the Sun, but a somewhat lower abundance of elements other than hydrogen and helium. It is spinning relatively quickly, with an estimated rotation period of 4.84 days. The surface magnetic field of the star has a complex and variable geometry. It is a BY Draconis variable star with an active chromosphere, which means there is a rotational modulation of its luminosity due to star spots.

CH Crucis is a solitary variable star in the southern constellation of Crux. It has the Gould designation 35 G. Crucis. The object is visible to the naked eye as a faint, blue-white hued point of light with an apparent visual magnitude that fluctuates around 4.91. The star is located approximately 780 light years distant from the Sun based on parallax, and is drifting further away with a radial velocity of about +12.5 km/s.

Toivara- Viitala's research examined the role women played in Egyptian life, particularly in terms of economics and administration. She was also an expert on Egyptian love poetry, personal names and hieroglyphics. Her work on papyrus manuscripts led to a collaboration examining the eclipsing variable star Algol, which was recorded in the Cairo Calendar. The link between the astronomical phenomenon and the specific manuscript was first raised by Toivara-Viitala and was widely reported, including in the New Scientist.

GY Andromedae (GY And) is an α2 Canum Venaticorum type variable star in the northern constellation Andromeda. Its brightness fluctuates in visual magnitude between 6.27m and 6.41m, making it a challenge to view with the naked eye even in good seeing conditions. The magnetic activity on this star shows an unusually long period of variability, cycling about once every 23 years. Based upon parallax measurements, this star is located at a distance of about from the Earth.

Visible in the same field and as prominent as the red supergiants in infrared images is the carbon star MZ Cephei, which is much closer to us than NGC 7419. It is a slow irregular variable star with a range of 14.7 - 15.4. The visually brightest star in the core region of the cluster is a yellow giant, placed at around 500 parsecs by Gaia astrometry. The even brighter nearby star HD 216721 is also a foreground object.

R Cygni light curve, showing the period-doubling R Cygni is a variable star of the Mira type in the constellation Cygnus, less than 4' from θ Cygni. This is a red giant star on the asymptotic giant branch located around 2,200 light years away. It is an S-type star ranging between spectral types S2.5,9e to S6,9e(Tc). Stars at this mass range and evolutionary stage are pulsationally unstable, displaying a variation in their light output.

It was first described by the Persian astronomer Al Sufi in his Book of Fixed Stars in 964. In the 17th century, it was independently rediscovered by the Italian astronomer G. B. Hodierna. In the 1920s, Dalmero Francis Brocchi, an amateur astronomer and chart maker for the American Association of Variable Star Observers (AAVSO), created a map of this object for use in calibrating photometers. In 1931, Swedish astronomer Per Collinder listed it in his catalogue of open clusters.

Curious spiral around red giant star R Sculptoris. No stars brighter than 3rd magnitude are located in Sculptor. This is explained by the fact that Sculptor contains the south galactic pole where stellar density is very low. Overall, there are 56 stars within the constellation's borders brighter than or equal to apparent magnitude 6.5. The brightest star is Alpha Sculptoris, an SX Arietis-type variable star with a spectral type B7IIIp and an apparent magnitude of 4.3.

16 Persei is a single, suspected variable star in the northern constellation of Perseus, located approximately 121 light years away based on parallax. It is visible to the naked eye as a yellow-white hued star with an apparent visual magnitude of 4.22. This object is moving further from the Earth with a heliocentric radial velocity of +14 km/s. It displays a relatively high proper motion, traversing the celestial sphere at the rate of per year.

8 Draconis is the star's Flamsteed designation. It also received the variable star designation IR Draconis in 2000, after its variability had been discovered using Hipparcos photometry. The star bore the traditional Chinese name of Taiyi, from 太乙 (Tài Yǐ) or 太一 (Tài Yī, the Great One), both of which refer to Tao. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars.

Betelgeuse is usually the tenth-brightest star in the night sky and, after Rigel, the second-brightest in the constellation of Orion. It is a distinctly reddish semiregular variable star whose apparent magnitude, varying between +0.0 and +1.6, has the widest range displayed by any first-magnitude star. At near-infrared wavelengths, Betelgeuse is the brightest star in the night sky. Its Bayer designation is α Orionis, Latinised to Alpha Orionis and abbreviated Alpha Ori or α Ori.

R Aquarii (R Aqr) is a variable star in the constellation Aquarius. R Aquarii is a symbiotic star believed to contain a white dwarf and a Mira-type variable in a binary system. The orbital period is approximately 44 years. The main Mira-type star is a red giant, and varies in brightness by a factor of several hundred and with a period of slightly more than a year; this variability was discovered by Karl Ludwig Harding in 1810.

Having exhausted the supply of hydrogen at its core, it has expanded to eight times the Sun's radius. It is a red clump giant, which indicates it is on the horizontal branch and is generating energy through helium fusion at its core. This is a suspected variable star with a magnitude that varies from 3.77 to 4.08 in the I passband. It is about 700 million years old with 2.4 times the mass of the Sun.

At an estimated distance of , this yields a physical size of about 16 times the radius of the Sun. Because of the star's mass and radius, it is emitting about 164 times the luminosity of the Sun. The abundance of elements other than hydrogen or helium, what astronomers term metallicity, is similar to the proportions in the Sun. This is a variable star that ranges in apparent visual magnitude from a low of 2.66 to a high of 2.60.

Amateur image of γ Cassiopeiae and the associated nebulae IC63 and IC59 (Neil Michael Wyatt) Gamma Cassiopeiae is an eruptive variable star, whose apparent magnitude changes irregularly between +1.6 and +3.0. It is the prototype of the class of Gamma Cassiopeiae variable stars. In the late 1930s it underwent what is described as a shell episode and the brightness increased to above magnitude +2.0, then dropped rapidly to +3.4. It has since been gradually brightening back to around +2.2.

NSV 1436 is a cataclysmic variable star in the constellation Perseus. It is a probable U Geminorum-type dwarf nova, and outbursts have been observed in 1948 and 2011. It is also listed in the General Catalogue of Variable Stars as V1024 Persei. V1024 Persei was initially named as Ross 4 in 1925, on the basis of photographic plates showing that it was much brighter in 1904 than in 1925. Another outburst was observed in November 1948.

In astronomy, a variable star designation is a unique identifier given to variable stars. It uses a variation on the Bayer designation format, with an identifying label (as described below) preceding the Latin genitive of the name of the constellation in which the star lies. See List of constellations for a list of constellations and the genitive forms of their names. The identifying label can be one or two Latin letters or a V plus a number (e.g. V399).

With the advent of photography the number of variables piled up quickly, and variable star names soon fell into the Bayer trap of reaching the end of the alphabet while still having stars to name. After two subsequent supplementary double- lettering systems hit similar limits, numbers were finally introduced. As with all categories of astronomical objects, names are assigned by the International Astronomical Union (IAU). The IAU delegates the task to the Sternberg Astronomical Institute in Moscow, Russia.

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.

About 145 light- years in diameter, M13 is composed of several hundred thousand stars, the brightest of which is a red giant, the variable star V11, with an apparent visual magnitude of 11.95. M13 is 22,200–25,000 light-years away from Earth. Single stars in this globular cluster were first resolved in 1779. Compared to the stars in the neighborhood of the Sun, the stars of the M13 population are more than a hundred times denser.

27 Canis Majoris is a binary star system in the northern constellation of Canis Major, located approximately 1,700 light years away from the Sun. It has the variable star designation EW Canis Majoris; 27 Canis Majoris is the Flamsteed designation. This system is visible to the naked eye as a dim, blue- white hued star with an apparent visual magnitude of +4.65. It is moving away from the Earth with a heliocentric radial velocity of 16 km/s.

UW Canis Majoris is a star in the constellation Canis Major. It is classified as a Beta Lyrae eclipsing contact binary and given the variable star designation UW Canis Majoris. Its brightness varies from magnitude +4.84 to +5.33 with a period of 4.39 days. Bode had initially labelled it as Tau2 Canis Majoris, but this designation had been dropped by Gould and subsequent authors. UW Canis Majoris A is a rare blue supergiant of spectral type O7.5-8 Iab.

His research publications run to more than forty articles in the areas of galactic structure, extragalactic nebulae cataloguing, variable star measurement, solar corona structure, and others. He was an exceptionally fine observer and possessed the added talent of clarity of style that made his articles models of scholarly writing. It is characteristic of his abiding interest in astronomy that he continued to publish research after becoming emeritus. His students include Elaine Nantkes, Lois Kiefer, David Heeschen, and Allan Sandage.

Having exhausted the supply of hydrogen at its core, this star expanded and cooled off the main sequence. At present it has 11 times the girth of the Sun. It is a suspected variable star of unknown type, with its brightness measured as varying from magnitude 5.30 down to 5.33. The star has 1.32 times the mass of the Sun and is radiating 61 times the Sun's luminosity from its swollen photosphere at an effective temperature of 4899 K.

Gamma Eridani (γ Eridani, abbreviated Gamma Eri, γ Eri), formally named Zaurak , is a variable star in the constellation of Eridanus. It is visible to the naked eye with an apparent visual magnitude that varies around 2.9, and lies at a distance of about 203 light years from the Sun, as determined by the Hipparcos astrometry satellite. This is an evolved red giant star that is currently on the asymptotic giant branch of the Hertzsprung–Russell diagram.

V4024 Sagittarii is a single variable star in the southern constellation of Sagittarius. It has a blue-white hue and is dimly visible to the naked eye with an apparent visual magnitude that fluctuates around 5.49. The star is located at a distance of approximately 1,700 light years based on stellar parallax, but is drifting closer with a radial velocity of −20 km/s. The position of this star near the ecliptic means it is subject to lunar occultations.

HD 143183 is a red supergiant variable star of spectral type M3Ia in constellation Norma. It is a member of the Norma OB1 association, at a distance of about 2 kiloparsecs. It is one of the most luminous red supergiants with a luminosity over 100,000 times greater than the Sun (), and is as well one of the largest stars with a radius more than a thousand times that of the Sun (). Older studies frequently calculated higher luminosities and radii.

It is a suspected eclipsing binary with a variable star designation V983 Centauri. The brighter member, designated component A, is a magnitude 4.52 chemically peculiar star of the helium-weak (CP4) variety, and has a stellar classification of B5 III-IVp. The spectrum of the star displays overabundances of elements such as nitrogen, phosphorus, manganese, iron, and nickel, while carbon, oxygen, magnesium, aluminium, sulfur, and chlorine appear underabundant relative to the Sun. Weak emission line features are also visible.

12 Camelopardalis is a binary star in the northern circumpolar constellation of Camelopardalis, located 700 light years away from the Sun as determined from parallax measurements. It forms a double star with 11 Camelopardalis, which is only 3 arcminutes away. The system has the variable star designation BM Camelopardalis; 12 Camelopardalis is the Flamsteed designation. It is just visible to the naked eye, appearing as a dim, orange-hued star with an apparent visual magnitude of 6.08.

BE Camelopardalis is a solitary variable star in the northern circumpolar constellation of Camelopardalis. It is visible to the naked eye as a faint, red-hued point of light with an apparent visual magnitude that fluctuates around 4.39. The star is located roughly 800 light years away from the Sun based on stellar parallax. This object is an M-type bright giant with a stellar classification of M2 II, and is currently on the asymptotic giant branch.

Although he uses a CCD camera, he is also good in visual estimates of star luminosity, reaching an accuracy of 0.03 magnitude (confirmed by separate photoelectric measurements). He has also been acknowledged for his numerous estimates and measurements of brightness and positions of comets and variable stars, as well as position measurements of minor planets. In 1993 he co-discovered (with Jan Kyselý) new variable star ES UMa. He is a member of the Czech Astronomical Society.

This would grow to become the Perkin- Elmer optical company, which was officially incorporated on April 19, 1937. Charles Elmer served as the secretary-treasurer of the Perkin-Elmer company until he retired in 1949. He was married to May Custer, the grand niece of General George Armstrong Custer. In 1937 he was awarded the Merit Award by the American Association of Variable Star Observers for his "long continued service and devotion to the activities of the Association".

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.

Rho1 Sagittarii, Latinized from ρ1 Sagittarii, is a single, variable star in the southern constellation of Sagittarius. It has a white hue and is visible to the naked eye with an apparent visual magnitude that fluctuates around 3.93. The distance to this star is approximately 127 light years based on parallax, and it is drifting further away with a radial velocity of +1.2 km/s. It is positioned near the ecliptic and so it can be occulted by the Moon.

The primary component, Gliese 282A, is a BY Draconis type variable star with a stellar classification of K2V. It has an effective temperature of 4,956 K. The companion, Gliese 282B, is a smaller, class K5V star. As of 2003, the pair had an angular separation of 58.30 arc seconds along a position angle of 113°. This is equivalent to a projected physical separation of 824 AU. There is a distant common proper motion companion (G 112-29) at an angular separation of 1.09°.

This system was found to have a variable radial velocity by Leah Allen and Adelaide Hobe of Lick Observatory in 1911. It was identified as a single-lined spectroscopic binary, and the orbital elements were published by Canadian astronomer W. E. Harper in 1926. The pair have an orbital period of 72.93 days and an eccentricity of 0.27. This is a RS Canum Venaticorum variable, indicating a close binary system with active star spots, and has the variable star designation BC Psc.

An artist's rendering of the Epsilon Aurigae system. The most prominent variable star in Auriga is Epsilon Aurigae (Al Maz, Almaaz), an F0 class eclipsing binary star with an unusually long period of 27 years; its last minima occurred in 1982–1984 and 2009–2011. The distance to the system is disputed, variously cited as 4600 and 2,170 light-years. The primary is a white supergiant, and the secondary may be itself a binary star within a large dusty disk.

Rather than being an intrinsically variable star, it is an eclipsing binary. Other notable star systems in Perseus include X Persei, a binary system containing a neutron star, and GK Persei, a nova that peaked at magnitude 0.2 in 1901. The Double Cluster, comprising two open clusters quite near each other in the sky, was known to the ancient Chinese. The constellation gives its name to the Perseus cluster (Abell 426), a massive galaxy cluster located 250 million light-years from Earth.

HR 4072 is a binary star system in the northern circumpolar constellation of Ursa Major. It has the variable star designation ET Ursae Majoris, abbreviated ET Uma, while HR 4072 is the system's designation from the Bright Star Catalogue. It has a white hue and is faintly visible to the naked eye with an apparent visual magnitude that fluctuates around 4.94. The system is located at a distance of approximately 339 light years from the Sun based on parallax measurements.

SX Phoenicis is a variable star in the southern constellation Phoenix. With an apparent visual magnitude ranging around 7.33, it is too faint to be seen with the naked eye. It is located 272 light years from the Sun, as determined from an annual parallax shift of . This is the prototype SX Phoenicis variable, which means it is a population II, high amplitude, pulsating variable. SX Phoenicis has a very low metallicity, with only 4% the proportion of iron of the Sun.

Light curve of semiregular variable star Betelgeuse Semiregular variable stars are giants or supergiants of intermediate and late spectral type showing considerable periodicity in their light changes, accompanied or sometimes interrupted by various irregularities. Periods lie in the range from 20 to more than 2000 days, while the shapes of the light curves may be rather different and variable with each cycle. The amplitudes may be from several hundredths to several magnitudes (usually 1-2 magnitudes in the V filter).

With the introduction of photometric instruments to astronomy, the variability of stars could now be monitored over intervals of time. Measurements of HD 196982 during 1969 showed them to be the most active flare stars known at that time: over a period of 16.31 hours, 54 flares were observed. The flares increased the combined magnitude of the pair by more than 0.05 for more than half of this observation period. By 1972, the pair had received the variable star designation AT Microscopii.

BQ Octantis (BQ Oct) is a variable star in the constellation Octans. It is an S-type star with an apparent magnitude of 6.82. It lies less than a quarter degree from the South Celestial Pole (SCP), making it the closest star to the SCP brighter than magnitude 10. While it is much nearer than Sigma Octantis (the star commonly used as the south pole star), it is too dim to the naked eye to use as a visual reference under typical skies.

They have reached approximately equal levels of carbon and oxygen in their atmospheres, which causes dramatic changes to the atmospheric chemistry which are visible in the spectrum. As an S star, its spectrum is classified as S5,1, with S5 approximately equivalent to the temperature of an M5 giant and the 1 indicating that the ZrO bands are relatively weak. BQ Octantis is a variable star. An amplitude of 0.05 magnitudes about an apparent magnitude of 6.82 has been derived from Hipparcos satellite photometry.

BC Canis Minoris is a variable star in the equatorial constellation of Canis Minor. It has a reddish hue and is just barely visible to the naked eye with an apparent visual magnitude that fluctuates around 6.30. The distance to this object is approximately 520 light years based on parallax, but it is drifting closer with a radial velocity of −67 km/s. This is an aging red giant star currently on the asymptotic giant branch with a stellar classification of M4/5III.

Pi1 Ursae Majoris (Pi1 UMa, π¹ Ursae Majoris, π¹ UMa) is a yellow G-type main sequence dwarf with a mean apparent magnitude of +5.63. It is approximately 46.8 light years from Earth, and is a relatively young star with an age of about 200 million years. It is classified as a BY Draconis type variable star and its brightness varies by 0.08 magnitudes. In 1986, it became the first solar-type star to have the emission from an X-ray flare observed.

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.

In solar physics he made a long photographic study of the sun, including hundreds of photographs taken in the violet light of calcium, using a Hilger spectroscope acquired by Father Perry. In this research he showed that the sun is spectroscopically, a variable star. During his time as president of the Branch, Sidgreaves carried out original work into the spectroscopy of novae. His work on Nova Aurigae, in 1892, contained some of the first photographs of the spectra of novae ever taken.

In 2003 he was awarded the William Tyler Olcott Award of the AAVSO, acknowledging him, among others, as a promoter of variable star observing and a mentor of amateur astronomers. By that time he contributed to the society's database with over 98,000 observations. The Milwaukee Astronomical Society named one of their two telescopes the "Edward A. Halbach Telescope" in his honour. On April 7, 2009 he celebrated his 100th birthday, a landmark that was noted on the NBC television program Today.

Based on an annual parallax shift of 13.45 mas, the distance to this star is around . The outer envelope of this star has an effective temperature of 7,550 K, giving it the yellow-white hued glow of an F-type star. It is a type of chemically peculiar star known as an Ap star, as indicated by the 'p' in the stellar classification. 10 Aql was described as a variable star in 1973 and a period of six days was suggested.

Its small amplitude, period, chemical peculiarity, and position in the H–R diagram indicated that it may be an α2 CVn variable and it was given this classification in the General Catalogue of Variable Stars, along with the variable star designation V1286 Aquilae. Later studies showed that the period was spurious and several very short pulsation periods were found: 11.6, 12.0, and 13.4 minutes. This indicated that 10 Aql was a member of the new rapidly oscillating Ap star class.

The visible component has a stellar classification of , matching a chemically peculiar B-type giant mercury-manganese star. Catalano and Leone (1991) found it to be a α2 CVn variable with a period of 4.6904 days, and thus it received the variable star designation PY And. It has an estimated 3.7 times the mass of the Sun and about 4.8 times the Sun's radius. It is radiating around 246 times the Sun's luminosity from its photosphere at an effective temperature of 12,882 K.

R Leporis (R Lep), sometimes called Hind's Crimson Star, is a well-known variable star in the constellation Lepus, near its border with Eridanus. It is designated "R" in the chart to the right. It is a carbon star which appears distinctly red. It is named after famous British astronomer J. R. Hind, who observed it in 1845. Its apparent magnitude varies from +5.5 to +11.7 with a period of 418-441 days; recent measurements give a period of 427.07 days.

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.

R Sct is the brightest of the RV Tau-type stars and the American Association of Variable Star Observers (AAVSO) contains over 110,000 observations of this star. At its brightest it is visible to the naked eye, and at its dimmest can be located with good binoculars. In the sky it is about 1 degree northwest of the Wild Duck Cluster (Messier 11). RV Tauri variables often have somewhat irregular light curves, both in amplitude and period, but R Scuti is extreme.

This is giving the star an oblate shape with an equatorial bulge that is an estimated 10% larger than the polar radius. Lambda Pavonis has 12.5 times the mass of the Sun and nine times the Sun's polar radius. It is radiating 8,450 times the luminosity of the Sun from its photosphere at an effective temperature of 20,300 K. Variations in signals coming from Lambda Pavonis have led to a debate on whether it is a binary, single or pulsating variable star.

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.

40 Eridani is the system's Flamsteed designation and ο² Eridani (Latinised to Omicron² Eridani) its Bayer designation. The designations of the sub-components - 40 Eridani A, B and C - derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU). 40 Eridani C also bears the variable star designation DY Eridani. The system bore the traditional name Keid derived from the Arabic word قيض meaning "(egg)shells" (cf.

The brightest member of NGC 6910 is a blue supergiant with spectral type B2 and apparent magnitude 7.0. It is located at the southeast edge of the cluster. It is also known as HD 194279 or V2118 Cygni and it is a variable star with P Cygni profile. A mag 8.1 star lies at the northwest edge of the cluster and a mag 8.5 O6 giant star (HD 229196 = V2245 Cygni) lies a bit southwest from the line connecting the two brightest stars.

IQ Aurigae is a (most likely) single, variable star in the northern constellation of Auriga. It is visible to the naked eye as a dim, white-hued star with an apparent visual magnitude that fluctuates around 5.38. The star is located at a distance of about 470 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +28.6 km/s. This is a magnetic Ap star with a stellar classification of A0pSi.

HD 90853 is a single star in the southern constellation Carina. It has the Bayer designation s Carinae, while HD 98053 is the identifier from the Henry Draper catalogue. This is a variable star with an apparent visual magnitude that ranges from 3.36 down to 3.51, and thus is bright enough to be visible to the naked eye. It is located at a distance of approximately 1,340 light years from the Sun based on parallax, and has an absolute magnitude of −4.44.

V533 Carinae was one of many small amplitude variable stars detected from an analysis of Hipparcos photometry. It was granted its variable star designation in 1999 as a batch of 2,675 new variables. It is classified as an Alpha Cygni type variable and its brightness varies from magnitude +4.69 to +4.75 as measured on the Hipparcos photometric scale. A period of 1.58499 days and an average visual amplitude of 0.0146 magnitudes are quoted although the variations are not strictly regular.

HD 92063 is a single star in the southern constellation of Carina. It has the Bayer designation t1 Carinae, while HD 92063 is the star's identifier from the Henry Draper Catalogue. This is a suspected variable star and is visible to the naked eye with an apparent visual magnitude of 5.08. The star is located at a distance of approximately 246 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −10 km/s.

V520 Carinae is a single star in the southern constellation of Carina. It has the Bayer designation w Carinae, while V520 Carinae is a variable star designation. The star has an orange hue and is faintly visible to the naked eye with an apparent visual magnitude that fluctuates around +4.58. It is located at a distance of approximately 1,140 light years from the Sun based on parallax, and it is drifting further away with a radial velocity of +9 km/s.

Columbus State University students are able to, upon training, use the WestRock Observatory as a research tool for various night- time projects. Current research topics, as of 2016, include narrowband and broadband nebulae and galaxy imaging, astrometric asteroid and comet orbit refinement, and variable star photometry. As the observatory undergoes upgrades, many more topics will be possible such as supernova remnants. In 2015, a group of student researchers sought out to give the WRO a Minor Planet Center Observatory Code.

Maia , designated 20 Tauri (abbreviated 20 Tau), is a star in the constellation of Taurus. It is a blue giant of spectral type B8 III, a chemically peculiar star, and the prototype of the Maia variable class of variable star. Maia is the fourth-brightest star in the Pleiades open star cluster (Messier 45), after Alcyone, Atlas and Electra. It is surrounded by one of the brighter reflection nebulae within the Pleiades, designated NGC 1432 and sometimes called the Maia Nebula.

Maia is a chemically peculiar star, meaning it has an unusual surface abundance of some elements as shown by its spectral lines. It is classified as a helium-weak star, but it also shows an excess of some elements including manganese. Maia was thought to be a variable star by astronomer Otto Struve. He proposed a class of stars known as Maia variables, which included Gamma Ursae Minoris, but Maia and some others in the class have since been found to be stable.

The Baade-Wesselink method is a method for determining the distance of a Cepheid variable star suggested by Walter Baade in 1926 and further developed by Adriaan Wesselink in 1946. In the original method the color of the star at various points during its period of variation is used to determine its surface brightness. Then, knowing the apparent magnitude at these points in time the angular diameter can be calculated. Measurements are also taken of the radial velocity using Doppler spectroscopy.

Rho Phoenicis (ρ Phoenicis) is a variable star in the constellation of Phoenix. From parallax measurements by the Gaia spacecraft, it is located at a distance of from Earth. This star is classified as an F-type giant with a spectral type of F3III, and in the HR diagram it occupies in the lower part of the instability strip. Rho Phoenicis is Delta Scuti variable, changing its visual apparent magnitude between 5.17 and 5.27 with a period of around 0.1–0.2 days.

He used the 6" refractor at the University of Leiden, for example, to make 36 variable star estimates for the AAVSO at this time. Later he visited American astronomer George W. Ritchey then on staff at the Observatoire de Paris where Ritchey told Ford all about his wish to create the 300" Apalantic Supertelescope. We now know this general design today as the Ritchey-Chrétien telescope. Ford also attended a meeting of the Société Astronomique de France while in Paris.

The campaign raised over , enough for one year of telescope time. Furthermore, as of 2016, more than fifty amateur astronomers working under the aegis of the American Association of Variable Star Observers were providing effectively full coverage since AAVSO's alert about the star in October 2015, namely a nearly continuous photometric record. In a study published in January 2018, Boyajian et al. reported that whatever is blocking Tabby's Star filters different wavelengths of light differently, so it cannot be an opaque object.

101 Piscium is a star in the zodiac constellation of Pisces, located around 1,400 light years away from the Sun. This appears as a dim, blue-white hued star near the lower limit of visibility to the naked eye at an apparent visual magnitude of 6.23. It is a suspected variable star with the designation NSV 559; 101 Piscium is the Flamsteed designation. The star is moving closer to the Earth with a heliocentric radial velocity of −10 km/s.

Mira B, also known as VZ Ceti, is the companion star to the variable star Mira, separated by around 100 AU. Suspected as early as 1918, it was visually confirmed in 1923 by Robert Grant Aitken, and has been observed more or less continually since then, most recently by the Chandra X-Ray Observatory. Long- known to be erratically variable itself, its fluctuations seem to be related to its accretion of matter from Mira's stellar wind, which makes it a symbiotic star.

The secondary is a flare star that is referred to as WX Ursae Majoris. It is characterized as a UV Ceti type variable star that displays infrequent increases in luminosity. This star was observed to flare as early as 1939 by the Dutch astronomer Adriaan van Maanen. Component B (WX Ursae Majoris) has been identified as an X-ray source, while no significant X-ray emission was detected from component A. This system had not been studied in X-rays prior to ROSAT.

It is a Delta Scuti variable star that cycles between magnitudes 4.15 and 4.21 every 59.388 minutes. The star displays an infrared excess, indicating the presence of a debris disk with a temperature of 65 K orbiting at a radius of 62 AU. This dust has a combined mass equal to 6.6% of the Earth's mass. There is a faint companion star at an angular separation of along a position angle of . This corresponds to a projected physical separation of .

AO Mensae is a single variable star in the southern circumpolar constellation of Mensa. It is too faint to be viewed with the naked eye, having an apparent visual magnitude that ranges from 9.96 down to 10.18. The star is 128 light years distant from the Sun based on parallax, and is drifting further away with a radial velocity of +16 km/s. It is a member of the Beta Pictoris moving group, a loose association of young stars moving through the galaxy.

TU Mensae is a cataclysmic variable star of (SU Ursae Majoris subtype) in the constellation Mensa. A close binary, it consists of a white dwarf and low mass star orbiting each other in 2 hours 49 minutes. The stars are close enough that the white dwarf strips material off the other star, creating an accretion disc that periodically ignites with a resulting brightening of the system. These result in an increase in brightness lasting around a day every 37 days.

It is drifting further away with a heliocentric radial velocity of +12.5 km/s. The primary component is an evolved giant star with a stellar classification of G8 III. It is a periodic variable star, showing a change in brightness with an amplitude of 0.004 magnitude at the rate of 7.50983 times per day. With the supply of hydrogen at its core exhausted, the star has cooled and expanded until now it has 10 times the radius of the Sun.

FK Comae Berenices is a variable star that varies in apparent magnitude between 8.14 and 8.33 over a period of 2.4 days. It is the prototype for the FK Comae Berenices (FK Com) class of variable stars. The variability of FK Com stars may be caused by large, cool spots on the rotating surfaces of the stars. This star is thought to be the result of a recent binary merger, resulting in a high rate of both spin and magnetic activity.

The two visibly distinguishable components of Albireo The large distance between the components, as well as their difference in color, make Albireo one of the easiest observable visual binaries. The brightest member, which is the third-brightest star in the constellation Cygnus, is actually a close binary itself. Also in the Cygnus constellation is Cygnus X-1, an X-ray source considered to be a black hole. It is a high-mass X-ray binary, with the optical counterpart being a variable star.

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.

Beta Piscium is a Be star, a special class of B-type stars with emission lines in their spectra. With a spectral type of B6Ve its mass is estimated to be about , and its radius is about . It is suspected to be a variable star. Beta Piscium is radiating 524 times the Sun's luminosity from its photosphere at an effective temperature of 15,500 K. The star has a high rate of spin, showing a projected rotational velocity of around 90 km/s.

RR Pictoris, also known as Nova Pictoris 1925, is a cataclysmic variable star system that flared up as a nova that lit up in the constellation Pictor in 1925. It was first noticed by South African astronomer R. Watson on 25 May 1925 when it had an apparent magnitude of 2.3. It continued to brighten to magnitude 1.2, which it reached on 9 June 1925. It dimmed to magnitude 4 by 4 July, but brightened again to 1.9 on 9 August.

The primary is classified as a Beta Cephei variable star that varies in brightness over a 0.1738-day period. The spectrum shows a radial velocity variation with the same period, indicating that the surface of the star is regularly pulsating outward and then contracting. This star is rotating rapidly, with a rotational velocity of 199 km/s along the equator. The secondary member of this system is one of the few stars whose spectrum is affected by the Struve–Sahade effect.

The system is most commonly referred to as UZ Fornacis, which is its variable star designation. The General Catalogue of Variable Stars describes it as "E+XM", meaning it is an eclipsing binary system consisting of a low-mass star with an X-ray-emitting companion. In the past the system has also been referred to using the designation EXO 033319–2554.2, which refers to its coordinates on the celestial sphere, as well as the EXOSAT satellite that detected it.

An FS Canis Majoris variable (FS CMa star) is a type of eruptive variable star. The class of variable stars are named after its prototype, FS Canis Majoris. They are somewhat poorly understood, most likely binary star systems in which mass exchange is ongoing or has recently happened, and most likely consist of at least one B-type main-sequence stars in a dust envelope. They undergo irregular light variations over long periods of time, with magnitude variation of approximately 2 magnitudes.

HD 130144 (or EK Boötis) is a semiregular variable star in the northern constellation of Boötes. The variation in luminosity has an amplitude of 0.38 in magnitude with no apparent periodicity. This is an X-ray source, and was possibly the first M-type giant star to have a magnetic field directly detected. It is considered to be a single star, although there is nearby companion at an angular separation of 0.2023″ along a position angle of 82.2° (as of 2010.4812).

28 Cancri is a star system in the zodiac constellation of Cancer. It is a variable star with the designation CX Cancri, and is close to the lower limit of visibility with the naked eye, having a mean apparent visual magnitude of 6.05. The annual parallax shift seen from Earth's orbit is 7.32 mas, which provides a distance estimate of about 450 light years. It is moving away from the Sun with a radial velocity of around +9 km/s.

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.

It is a slow irregular variable star of type Lb, undergoing changes in magnitude over the range 3.57−3.72 with a periodicity of 23.8 d. The measured angular diameter of Tau4 Eridani is . At its estimated distance, this yields a physical size of about 106 times the radius of the Sun. It shines with 1,537 times the luminosity of the Sun from an outer atmosphere at an effective temperature of 3,712 K. This is most likely a binary star system.

It should achieve perihelion in about two million years, approaching as close as . This is an evolved giant star with a stellar classification of K2 III, having exhausted the supply of hydrogen at its core and moved off the main sequence. It is a suspected variable star, possibly of the micro-variable variety, having an amplitude of less than 0.03 in magnitude. 14 Sagittarii is radiating about 317 times the Sun's luminosity from its photosphere at an effective temperature of around 3,940 K.

IRC+10420 and its circumstellar material IRC+10420 was first identified in the 1969 Infrared Catalogue of 2.2 micron sources. It was quickly noted as a very unusual object after being detected at 20 microns as one of the brightest sources in the sky with a large infrared excess, and was compared to Eta Carinae during one of its outbursts. It was also discovered to be a strong source of OH maser emission. It was formally catalogued as variable star V1302 Aquilae.

It is a suspected variable star of unknown type, with an I-band brightness ranging from 3.29 down to 3.44 magnitude. Hipparcos photometry revealed a microvariability with a frequency of 0.17017 cycles per day and an amplitude of 0.0080. With the supply of hydrogen exhausted at its core, it has expanded and now has 48 times the Sun's girth. The star is radiating 492 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 3,930 K.

Iota Canis Majoris (ι Canis Majoris, ι CMa) is a variable supergiant star in the constellation Canis Major. Iota Canis Majoris is a blue-white B-type supergiant with an apparent magnitude that varies between +4.36 and +4.40. It has been classified as a Beta Cephei type variable star, but the supergiant spectral type and a period of over a month mean it is no longer considered to be of that type. It is approximately 3,100 light years from Earth.

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.

Pleione (pronounced or ) is a binary star and the seventh-brightest star in the Pleiades star cluster (Messier 45). It has the variable star designation BU Tauri (BU Tau) and the Flamsteed designation 28 Tauri (28 Tau). The star is located approximately from the Sun, appearing in the constellation of Taurus. Pleione is located close on the sky to the brighter star Atlas, so is difficult for stargazers to distinguish with the naked eye despite being a fifth magnitude star.

28 Tauri is the star's Flamsteed designation and BU Tauri its variable star designation. The name Pleione originates with Greek mythology; she is the mother of seven daughters known as the Pleiades. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included Pleione for this star.

V810 Centauri is a double star consisting of a yellow supergiant primary (V810 Cen A) and blue giant secondary (V810 Cen B). It is a small amplitude variable star, entirely due to the supergiant primary which is visually over three magnitudes brighter than the secondary. It is the MK spectral standard for class G0 0-Ia. V810 Cen A shows semi-regular variations with several component periods. The dominant mode is around 156 days and corresponds to Cepheid fundamental mode radial pulsation.

M31-RV is a possible red cataclysmic variable star located in the Andromeda Galaxy that experienced an outburst in 1988, which is similar to the outburst V838 Monocerotis experienced in 2002. Such objects have been called Luminous Red Novae or intermediate-luminosity red transients. During the outburst, both V838 Mon and M31-RV reached a maximum absolute visual magnitude of -9.8. In 2006, the area around M31-RV was observed using the Hubble Space Telescope, but only red giants were seen.

Xi Ursae Majoris (ξ Ursae Majoris, abbreviated Xi UMa, ξ UMa), also named Alula Australis , is a star system in the constellation of Ursa Major. On May 2, 1780, Sir William Herschel discovered that this was a binary star system, making it the first such system ever discovered. It was the first visual double star for which an orbit was calculated, when it was computed by Félix Savary in 1828. It is also a variable star with a small amplitude.

HD 160342 is the Henry Draper Catalogue designation for a star in the southern constellation of Ara. It has an apparent visual magnitude of 6.35 and, based upon parallax measurements, is approximately distant from Earth. This is an evolved red giant that is on the asymptotic giant branch, with a stellar classification of M3 III. It is a periodic variable star that changes in brightness by 0.1127 magnitudes at the rate of 0.37943 cycles per day, or once every 2.6 days.

Peter Francis Williams is an amateur astronomer from New South Wales, Australia. He specializes in early detection of declines in R Coronae Borealis-type stars and the long-term monitoring of several southern Mira variables and eclipsing binary stars. He was the first person who detected the naked-eye Nova known as V382 Velorum in 1999 and seven years later he discovered the Nova Ophiuchi 2006. Both discoveries brought him the Nova/Supernova Award of the American Association of Variable Star Observers.

Omega Ophiuchi, which is Latinized from ω Ophiuchi, is a single, variable star in the equatorial constellation of Ophiuchus, located just to the north of the ecliptic near the western constellation border with Scorpius. It is a white- hued star that is faintly visible to the naked eye with an apparent visual magnitude that fluctuates around 4.45. Parallax measurements indicate it lies at a distance of about 168.6 light years from the Sun. It is drifting further away with a radial velocity of +2.5 km/s.

As such it is generating energy at a higher rate than the Sun, with a luminosity 14 times greater. The outer atmosphere has an effective temperature of 8,930 K, which is what gives it the white-hued glow of an A-type star. It is classified as a Delta Scuti type variable star and its brightness varies by 0.02 magnitudes over periods of 0.5 to 2.4 hours. This star has been established as a Lambda Boötis star that displays low abundances of iron peak elements.

This is a K-type giant star with a stellar classification of K4.5 III. It is a suspected variable star with a reported magnitude range of 4.28−4.34. The interferometry-measured angular diameter of this star, after correcting for limb darkening, is , which, at its estimated distance, equates to a physical radius of nearly 45 times the radius of the Sun. It shines with around 472 times the luminosity of the Sun, from an outer atmosphere that has an effective temperature of 3,900 K.

The dimensions of the bow shock are vast: around 12 light-years long and 1.8 light-years wide. Theta Cassiopeiae, named Marfak, is a suspected variable star whose brightness changes by less than a tenth of a magnitude. Iota Cassiopeiae is a triple star 142 light-years from Earth. The primary is a white-hued star of magnitude 4.5 and an α2 Canum Venaticorum variable, the secondary is a yellow-hued star of magnitude 6.9, and the tertiary is a star of magnitude 8.4.

V602 Carinae (V602 Car, HD 97671) is a red supergiant and variable star of spectral type of M3 in the constellation Carina. It is one of largest known stars. In 2005, V602 Car was calculated to have a bolometric luminosity below and a radius around based on the assumption of an effective temperature of . A 2015 study derived a slightly higher bolometric luminosity of based on the measured flux and an assumed distance, and a larger radius of based on the measured angular diameter and luminosity.

Gamma Phoenicis is a star system in the constellation Phoenix, located around distant. γ Phoenicis is a spectroscopic binary and a small amplitude variable star. The star system shows regular variations in brightness that were reported as a 97.5 day period in the Hipparcos catalogue, but have since been ascribed to a 193-day orbital period with primary and secondary minima. Although the light curve appears to show eclipses, the high orbital inclination suggests the variations are due to ellipsoidal stars as they rotate in their orbit.

Because of its position near the winter Milky Way, Auriga has many bright open clusters in its borders, including M36, M37, and M38, popular targets for amateur astronomers. In addition, it has one prominent nebula, the Flaming Star Nebula, associated with the variable star AE Aurigae. In Chinese mythology, Auriga's stars were incorporated into several constellations, including the celestial emperors' chariots, made up of the modern constellation's brightest stars. Auriga is home to the radiant for the Aurigids, Zeta Aurigids, Delta Aurigids, and the hypothesized Iota Aurigids.

French explorer and astronomer Nicolas-Louis de Lacaille gave Bayer designations to its stars in 1756, some of which had been previously considered part of the neighbouring constellation Piscis Austrinus. The constellations Grus, Pavo, Phoenix and Tucana are collectively known as the "Southern Birds". The constellation's brightest star, Alpha Gruis, is also known as Alnair and appears as a 1.7-magnitude blue-white star. Beta Gruis is a red giant variable star with a minimum magnitude of 2.3 and a maximum magnitude of 2.0.

The yellow supergiant R Coronae Borealis is the prototype of a rare class of giant stars—the R Coronae Borealis variables—that are extremely hydrogen deficient, and thought to result from the merger of two white dwarfs. T Coronae Borealis, also known as the Blaze Star, is another unusual type of variable star known as a recurrent nova. Normally of magnitude 10, it last flared up to magnitude 2 in 1946. ADS 9731 and Sigma Coronae Borealis are multiple star systems with six and five components respectively.

A very young star, it is still accumulating interstellar material. It is obscured by, and illuminates, the surrounding nebula, NGC 6729, which brightens and darkens with it. The nebula is often compared to a comet for its appearance in a telescope, as its length is five times its width. S Coronae Australis is a G-class dwarf in the same field as R and is a T Tauri star. Nearby, another young variable star, TY Coronae Australis, illuminates another nebula: reflection nebula NGC 6726–7.

Harriman appears in "Requiem" as an old man who has still not been able to go to the Moon. It was published in 1940, 11 years before The Man Who Sold the Moon. The name "Harriman" reappears in many Future History stories as the name of various businesses and foundations, indicating that Harriman's impact on that timeline is significant. The name is also used in Variable Star, a novel outlined by Heinlein but written by Spider Robinson following Heinlein's death; the novel diverges from the Future History.

Rho Pavonis, Latinized from ρ Pavonis, is a single, variable star in the southern constellation of Pavo. It is yellow-white in hue and faintly visible to the naked eye with an apparent visual magnitude that fluctuates around 4.86. The star is located at a distance of approximately 190 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +8 km/s. It is a candidate outlying member of the Tucana Association of co- moving stars.

BU Canis Minoris is a binary star system in the equatorial constellation of Canis Minor. It has the Henry Draper Catalogue designation of HD 65241, while BU Canis Minoris is its variable star designation. The system is a challenge to view with the naked eye, having a peak apparent visual magnitude of 6.42. It is located at a distance of approximately 700 light years from the Sun based on parallax, and is drifting further away with a radial velocity of about +34 km/s.

Brunhild (minor planet designation: 123 Brunhild) is a stony S-type main-belt asteroid. It was discovered by German-American astronomer C. H. F. Peters on July 31, 1872, and named after Brünnehilde, a Valkyrie in Norse mythology. Brunhild has been mistaken for the non-existent variable star KN Gem. In 1983, 123 Brunhild was observed photometrically from the Observatoire de Haute- Provence, producing an irregular light curve that showed eight extremes, including two minima and two maxima that were more accentuated than the others.

At that range, the visual magnitude of the star is diminished by an extinction of due to interstellar dust. It is moving further from the Earth with a heliocentric radial velocity of +19 km/s. This is an aging red giant star with a stellar classification of M2.5 III, which indicates it has exhausted the hydrogen at its core and evolved away from the main sequence. It is a suspected variable star that may vary in brightness with an amplitude of 0.07 in magnitude.

At present Rho Puppis is moving away from the Sun with a radial velocity of +46.1 km s−1. The closest approach occurred about 394,000 years ago when it came within roughly of the Solar System; about the same distance as Procyon in the present era. The variability of this star was announced in 1956 by American astronomer Olin J. Eggen. It was determined to be a Delta Scuti-type variable star, making it one of the first stars of that type to be identified.

Observations of comets and stars are also used to measure the local level of artificial skyglow. One branch of amateur astronomy, amateur astrophotography, involves the taking of photos of the night sky. Many amateurs like to specialize in the observation of particular objects, types of objects, or types of events that interest them. The American Association of Variable Star Observers has gathered data on variable stars for educational and professional analysis since 1911 and promotes participation beyond its membership on its Citizen Sky website.

SS Cygni in outburst versus its quiet state SS Cygni is a variable star in the northern constellation Cygnus (the Swan). It is the prototype of the subclass of dwarf novae that show only normal eruptions. It typically rises from 12th magnitude to 8th magnitude for 1–2 days every 7 or 8 weeks. The northerly declination of SS Cygni (about 44° N) makes the star almost circumpolar from European and North American latitudes, allowing a large proportion of the world's amateur astronomers to monitor its behavior.

Based upon an annual parallax shift of 7.53 milliarcseconds, the distance to this star is about . This is an evolved giant star with a stellar classification of K3 III. It has expanded to 37 times the radius of the Sun and is radiating 434 times the luminosity of the Sun from its outer envelope at an effective temperature of 4,170 K. This gives it the orange-hued glow of a K-type star. It is a suspected variable star that ranges in magnitude between 4.66 and 4.71.

It is classified as an Alpha Cygni type variable star and its brightness varies by a few hundredths of a magnitude. Periods of two hours, nine days, and 2.65 days have been reported from observations at different times. It is a runaway star, moving at around 2.5 million mph relative to its neighbors (1,100 kilometers per second). Its magnetic field and wind of particles creates a visible bow shock 4 light-years ahead of it, colliding with the diffuse, and usually invisible, interstellar gas and dust.

So, among the shots I took after > publishing the paper were some from Germany that said, "You know, you really > named it after the wrong person." Which I knew very well. While Eddy did not predict the next significant solar minimum he did identify that we are living by the light of a variable star and it is for this reason it is said that the next significant solar minimum should be named in his honor. He cautioned:The Sun: A Biography by David Whitehouse, page 225.

Kappa Ophiuchi (κ Oph, κ Ophiuchi) is a star in the equatorial constellation Ophiuchus. It is a suspected variable star with an average apparent visual magnitude of 3.20, making it visible to the naked eye and one of the brighter members of this constellation. Based upon parallax measurements made during the Hipparcos mission, it is situated at a distance of around from Earth. The overall brightness of the star is diminished by 0.11 magnitudes due to extinction from intervening matter along the line of sight.

SS Ursae Minoris is a cataclysmic variable star system in the constellation Ursa Minor. It was discovered visually and by its X-ray emissions separately in 1982 before they were understood to be coming from the same object. It is classified as a SU Ursae Majoris variable subclass of dwarf nova in that it has both 'normal' outbursts of increased brightness as well as even brighter 'superoutbursts'. However, unlike other SU Ursae Majoris stars, the superoutbursts are of longer duration than the regular outbursts.

A small telescope is generally considered by professional astronomers to be any reflecting telescope with a primary mirror that is less than in diameter. By amateur standards, a small telescope can have a primary mirror/aperture less than in diameter. Little if any professional-level research is performed with refracting telescopes in the modern era of astronomy. Small telescopes dominate astronomical research in the fields of asteroid/comet discovery/observation, variable star photometry, supernova/nova discovery, and colorimetry/polarimetry of the Solar System's planets.

The primary, component A, is a variable star, most likely of the slow irregular type, which ranges in magnitude from 4.91 down to 4.96. It is a giant star with a stellar classification of K3 III, which indicates it has exhausted the hydrogen at its core and evolved away from the main sequence. The measured angular diameter of this star, after correction for limb darkening, is . At the estimated distance of this star, this yields a physical size of about 27 times the Sun's radius.

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.

Ross 548 is a variable white dwarf star of the DAV type. It was found to be variable in 1970;High-Frequency Stellar Oscillations. VI. R548, a Periodically Variable White Dwarf, Barry M. Lasker and James E. Hesser, Astrophysical Journal 163 (February 1971), pp. L89-L93. in 1972, it was given the variable star designation ZZ Ceti,58th Name-List of Variable Stars, B. V. Kukarkin, P. N. Kholopov, N. P. Kukarkina, N. B. Perova, Information Bulletin on Variable Stars, #717, September 21, 1972.

HD 29697 is the Henry Draper Catalogue number of this star. It is also known by its designation in the Gliese Catalogue of Nearby Stars, Gliese 174, and its variable star designation V834 Tauri. V834 Tauri is a BY Draconis variable with maximum and minium apparent magnitudes of 7.94 and 8.33 respectively, so it is never visible to the naked eye. The star has been examined for indications of a circumstellar disk using the Spitzer Space Telescope, but no statistically- significant infrared excess was detected.

The system shows variable brightness and spectral line profiles. The companion has a very low mass and luminosity and orbits the primary in 288 days. The primary component has a stellar classification of F2Ibe, and is among a rare class of post-asymptotic giant branch stars – low mass stars in the last stages of their lives, highly inflated to appear as supergiants. It is classified as a semiregular variable star, subtype SRd, and ranges from magnitude 5.3 down to 5.5 over a period of around 68 days.

Omicron Andromedae is a Gamma Cassiopeiae type variable star and the system's brightness varies from magnitude +3.58 to +3.78. The variable component is the brightest and most massive star in the system, Aa. The spectrum is predominantly that of a B6 giant star, from the brightest component in the system. It is a shell star and the spectrum contains emission lines with variable profiles. Spectral lines similar to an A2 star are also detectable in the spectrum and these are thought to originate in the B component.

The star has an absolute magnitude of −3.77, and is drifting further away with a radial velocity of +9.9 km/s. This object is a massive, aging bright giant with a stellar classification of K3II-IIb. It is a suspected variable star that fluctuates in magnitude by an amplitude of 0.05 in the B-band of the UBV photometric system. With the supply of hydrogen exhausted at its core, it has evolved of the main sequence and cooled and expanded to 156 times the Sun's radius.

This is a double-lined spectroscopic binary system with an essentially circular orbit and a period of one week. The primary component is a chemically peculiar star of type CP1, or Am star, with a stellar classification of A8m. Abt and Morrell (1995) classed it as Am(A7/F0/F2), indicating it has the hydrogen lines of an A7 star, the calcium K line of a cooler F0 star, and the metallic kines of an F2 class. It has been mentioned as a potential variable star.

HD 39225, also known as HR 2028, is a variable star in the northern constellation Auriga, located around 620 light years away from the Sun. It is visible to the naked eye as a faint, red-hued star with an apparent visual magnitude of around 6.04. This is a suspected runaway star that is moving away from the Sun with a heliocentric radial velocity of 98 km/s. Currently on the asymptotic giant branch, this is an evolved red giant star with a stellar classification of .

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.

ADS 1359 was discovered by the Hipparcos spacecraft to be a detached eclipsing binary and given the variable star designation V773 Cassiopeiae. The derived period of variability was 1.29 days, exactly half the orbital period of the inner pair since each orbit produces two almost-identical eclipses. The eclipsing stars are the inner pair of the system. The two stars combined are still about eight times fainter than the third star and so the eclipses decrease the overall brightness of V773 Cas by less than 0.1 magnitudes.

In 1965, Neugebauer, Martz, and Leighton, astronomers with the California Institute of Technology, reported the discovery of two extremely cool stars. At the time, the temperatures of these extremely red objects were estimated to be around 1,000 K. In the absence of other designations, these were named after the initials of their discoverers as NML Cygni and NML Tauri. It was identified as a Mira variable in 1967. The name NML Tauri fell into disuse after the star received its variable star designation of IK Tauri.

Iota Hydrae (ι Hydrae, abbreviated Iota Hya, ι Hya), formally named Ukdah , is a star in the constellation of Hydra, about 8° to the north-northwest of Alphard (Alpha Hydrae) and just to the south of the celestial equator. Visible to the naked eye, it is a suspected variable star with an apparent visual magnitude that ranges between 3.87 and 3.91. Based upon an annual parallax shift of 12.39 mas measured during the Hipparcos mission, it is located around 263 light-years from the Sun.

It was discovered by the robotic sky survey ATLAS on January 12.30, 2019, using a twin 0.5m telescope system. It had apparent magnitude 18.9 on discovery. The supernova was initially classified as a type II supernova with spectroscopic observations by Keck-II, and further spectrographic observations categorised it as type IIb, although it could also be a cataclysmic variable or another type of variable star. NGC 877 forms a pair with the edge-on spiral galaxy NGC 876, which lies 2.1 arcminutes to the southwest.

This object is drifting closer with a radial velocity of −13 km/s. This is an evolved red giant star with a stellar classification of M2 III. It is a variable star of uncertain type, showing a change in brightness with an amplitude of 0.0114 magnitude and a frequency of 0.22675 cycles per day, or 4.41 days/cycle. It has about 67 times the Sun's radius and is radiating 975 times the Sun's luminosity from its photosphere at an effective temperature of 3,936 K.

This caused bluer stars to have a brighter photographic magnitude against the equivalent visual magnitude: appearing brighter on the photograph than the human eye or modern electronic photometers. Conversely, redder stars appear dimmer, and have a fainter photographic magnitude than its visual magnitude. For example, the red supergiant star KW Sagittarii has the photographic magnitude range of 11.0p to 13.2p but in the visual magnitude of about 8.5p to 11.0p. It is also common for variable star charts to feature several blue magnitude (B) comparison stars. e.g.

W Canis Majoris (W CMa) is a carbon star in the constellation Canis Major. A cool star, it has a surface temperature of around 2,900 K and a radius 234 times that of the Sun, with a bolometric absolute magnitude of −4.13 and distance estimated at 443 or 445 parsecs (1,444–1,450 light-years) based on bolometric magnitude or radius. The Gaia Data Release 2 parallax of implies a distance of about 555 parsecs. W CMa is classified as a slow irregular variable star.

From 1700 until 1718 he worked on a catalog of fixed stars, and from 1672 until 1719 he studied Mars extensively. His most famous astronomical discovery was that the ice caps on Mars are not exactly on the rotational poles of that body. He also recognized (in May 1724) that the corona visible during a solar eclipse belongs to the Sun not to the Moon, and he discovered R Hydrae as a variable star. He also helped with the survey based on the Paris Meridian.

HD 70573 is a variable star in the equatorial constellation of Hydra. At a mean apparent visual magnitude of +8.71, this yellow-hued star is too dim to be visible to the naked eye. Based upon parallax measurements, it is located at a distance of 193 light years from the Sun, and is drifting further away with a radial velocity of 20.5 km/s. It is a candidate member of the proposed Hercules-Lyra Association of co-moving stars, although this membership is disputed.

BX Circini is a star in the constellation Circinus. Its variability was discovered in 1995, with its apparent magnitude ranging from 12.57 to 12.62 over a period of 2 hours 33 minutes. It is currently classified as a PV Telescopii variable star, but has been put forward as the prototype of a new class of pulsating star—the BX Circini variables—along with the only other known example, V652 Herculis. This class of star is rare, possibly because this is a brief stage of stellar evolution.

The investigators proposed that the emission lines have arisen from an accretion disc around a white dwarf rather than from the star itself. The system is poorly known, though the donor star has been calculated to be of spectral type F5V. These stars have spectra very similar to novae that have returned to quiescence after outbursts, yet they have not been observed to have erupted themselves. The American Association of Variable Star Observers recommends watching this class of star for future events such as possible nova eruptions.

The rise to peak brightness may be very rapid, or gradual. This is related to the speed class of the nova; yet after the peak, the brightness declines steadily.AAVSO Variable Star Of The Month: May 2001: Novae The time taken for a nova to decay by around 2 or 3 magnitudes from maximum optical brightness is used for classification, via its speed class. Fast novae typically will take fewer than 25 days to decay by 2 magnitudes, while slow novae will take more than 80 days.

With an overall magnitude of 8.0, it is significantly dimmer than the Great Orion Nebula that lies to its south; however, it is at approximately the same distance, at 1600 light-years from Earth. It can easily be mistaken for a comet in the eyepiece of a telescope. M78 is associated with the variable star V351 Orionis, whose magnitude changes are visible in very short periods of time. Another fairly bright nebula in Orion is NGC 1999, also close to the Great Orion Nebula.

Henden was also part of the team that created specifications for the Discovery Channel's 4.2m telescope. He has also worked on the Sloan Digital Sky Survey and consulted for the Radio Astronomy Institute in developing a robotic observatory near the Grand Canyon. In the Spring of 2004, Henden was named Director of the American Association of Variable Star Observers (AAVSO), an organization he had long been a member of. Henden has authored more than 100 articles in peer-reviewed publications as either primary or co-author.

DN Geminorum or Nova Geminorum 1912 was a classical nova which lit up in 1912 in the constellation Gemini. It was discovered by Norwegian variable star observer Sigurd Einbu on March 12, 1912 before reaching peak brightness, which allowed early-stage spectra to be collected by Yerkes Observatory. The nova reached a maximum brightness of around 3.5 mag before declining, which means it was visible to the naked eye. Its brightness decreased over the following 36 days by 3 magnitudes as it gradually faded from sight.

Analysis of Hipparcos photometry shows an amplitude of 0.082 magnitudes and a primary period of 4.76 days. It has not yet been assigned a variable star designation in the General Catalogue of Variable Stars and is still formally listed as a suspected variable. The hydrogen-rich WN stars have been referred to as WNL stars or as WNH stars since they do not necessarily have late nitrogen-sequence spectra. They are systematically more massive and more luminous than stars with similar spectra but lacking nitrogen.

Epsilon Pegasi has been observed to brighten radically upon a few occasions, giving rise to the theory that it (and possibly other supergiants) erupt in massive flares that dwarf those of the Sun. It is a type LC slow irregular variable star that varies from +0.7 to +3.5 in magnitude. The spectrum shows an overabundance of the elements strontium and barium, which may be the result of the S-process of nucleosynthesis in the outer atmosphere of the star. It has a relatively high peculiar velocity of .

In a telescope the "star" is framed within the dark "V" dust lane of the nebula and appears distinctly orange and clearly non-stellar. High magnification will show the two orange lobes of a surrounding reflection nebula known as the Homunculus Nebula on either side of a bright central core. Variable star observers can compare its brightness with several 4th- and 5th-magnitude stars closely surrounding the nebula. Discovered in 1961, the weak Eta Carinids meteor shower has a radiant very close to Eta Carinae.

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.

This is an aging giant star with a stellar classification of K5 III, indicating it has exhausted the hydrogen at its core and evolved off the main sequence. It is a suspected variable star of unknown type. The interferometry-measured angular diameter of the primary component, after correcting for limb darkening, is , which, at its estimated distance, equates to a physical radius of about 54 times the radius of the Sun. It is around 1.15 billion years old with 1.4 times the mass of the Sun.

The brighter component is an aging red giant with a stellar classification of M2III. It is currently on the asymptotic giant branch, indicating this is a highly evolved star that has exhausted both its core hydrogen and core helium. This is a suspected variable star. It has expanded to 53 times the radius of the Sun and is radiating 587 times the Sun's luminosity from its swollen photosphere at an effective temperature of 3,885 K. A 9th magnitude companion star is located one arc second away.

The 'n' suffix indicates "nebulous" absorption lines due to rapid rotation, and it shows a relatively high projected rotational velocity of 109.2 km/s. It is a variable star of unknown type that varies in brightness with an amplitude of 0.05 magnitude. The star is about 570 million years old and it has an estimated mass of 1.47 times the mass of the Sun. On average, it is radiating 25 times the Sun's luminosity from its photosphere at an effective temperature of 7,240 K.

Three of this stars were found to be spectrographic binaries, while further studies indicated that one of them is a triple system. Two more are suspected double stars. Further studies revealed seven variable stars, 5 eclipsing binaries, one delta Scuti variable and one gamma Doradus variable, with the gamma Doratus variable star membership being questionable. From the eclipsing binaries, one is field star and in a further study one more eclipsing binary (specifically a W Ursae Majoris variable) was found to lie at the background.

FL Lyrae is the variable star designation for an eclipsing binary star system in the northern constellation of Lyra. The combined apparent magnitude of the pair is 9.36, which means they are too faint to be seen with the naked eye. Parallax measurements from the Hipparcos spacecraft put the system at a distance of around 420 light years from the Sun. This star system was in the view field of the Kepler space telescope during 2009−2014, which allowed monitoring during that spacecraft's mission.

BP Boötis is a solitary variable star in the northern constellation of Boötes, near the northern constellation border with Draco. It is visible to the naked eye as a dim, white-hued star with an apparent visual magnitude that fluctuates around 5.48. The star is located 299 light years away from the Sun based on parallax, but is drifting closer with a radial velocity of −16 km/s. This is an Ap star with a stellar classification of , showing abundance anomalies of silicon and chromium.

HD 37017 is a binary star system in the equatorial constellation of Orion. It has the variable star designation V1046 Orionis; HD 37017 is the identifier from the Henry Draper Catalogue. The system is a challenge to view with the naked eye, being close to the lower limit of visibility with a combined apparent visual magnitude of 6.55. It is located at a distance of approximately 1,230 light years based on parallax, and is drifting further away with a radial velocity of +32 km/s.

It is classified as a semiregular variable star, showing a periodicity of 66.8 days with an amplitude of 0.0202 in visual magnitude. Iota Tucanae is an X-ray source with a luminosity of . It has an estimated 2.2 times the mass of the Sun, and, at the age of 1.69 billion years, it has evolved away from the main sequence, expanding to 11 times the Sun's radius. The star radiates 65 times the solar luminosity from its photosphere at an effective temperature of 5,039 K.

Like Luyten 726-8A, this star was also found to be variable and given the variable star designation UV Ceti. Although UV Ceti was not the first flare star discovered, it is the most prominent example of such a star, so similar flare stars are now classified as UV Ceti type variable stars. This star goes through fairly extreme changes of brightness: for instance, in 1952, its brightness increased by 75 times in only 20 seconds. UV Ceti is a red dwarf of spectral type M6.0e.

53 Camelopardalis is a binary star system in the northern circumpolar constellation of Camelopardalis, located 290 light years away from the Sun as determined by parallax measurements. It has the variable star designation AX Camelopardalis; 53 Camelopardalis is the Flamsteed designation. This object is dimly visible to the naked eye as a white hued star with a baseline apparent visual magnitude of +6.02. It is a single-lined spectroscopic binary system with an orbital period of 6.63 years and a high eccentricity of 0.718.

11 Camelopardalis and its reddish companion 12 Camelopardalis 11 Camelopardalis is a single star in the northern circumpolar constellation of Camelopardalis, located around 710 light years away from the Sun as determined by parallax. It has the variable star designation BV Camelopardalis; 11 Camelopardalis is the Flamsteed designation. This object is visible to the naked eye as a faint, blue-white hued star with a baseline apparent visual magnitude of +5.22. It forms a double star with 12 Camelopardalis, which is only 3 arcminutes away.

VZ Camelopardalis is a single, variable star in the northern circumpolar constellation of Camelopardalis. It has a reddish hue and is faintly visible to the naked eye with an apparent visual magnitude that fluctuates around 4.92. The star is located at a distance of approximately 500 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +12 km/s. It was considered a member of the Hyades Supercluster, but in 1990 this was brought into question.

RX Andromedae is a variable star in the constellation of Andromeda. Although it is classified as a dwarf nova of the Z Camelopardalis (UGZ) type, it has shown low-luminosity periods typical of VY Sculptoris stars. However, for most of the time it varies from an apparent visual magnitude of 15.1 at minimum brightness to a magnitude of 10.2 at maximum brightness, with a period of approximately 13 days.RX And, database entry, Combined General Catalog of Variable Stars (GCVS4.2, 2004 Ed.), N. N. Samus, O. V. Durlevich, et al.

Horace Clifford Levinson (30 June 1895, Chicago – 1968, Kennebunk, Maine) was an American mathematician, astronomer, and pioneer of operations research, introducing quantitative methods and sophisticated mathematical models into advertising and merchandising. Horace C. Levinson's father was the noted Chicago lawyer Salmon Oliver Levinson. In 1909 the Society of Practical Astronomical was founded by two teenagers: Frederick Charles Leonard (1896–1960) as president and H. C. Levinson as treasurer. The Society was disbanded in 1917, but it played a significant role in the history of the American Association of Variable Star Observers.

AM Herculis was first cataloged in 1923 by Max Wolf and was listed at the time as Veränderlicher 28.1923, which is now AN 28.1923 in the General Catalogue of Variable Stars. It was observed to be an irregular variable star ranging from 12 to 14 in apparent magnitude. In 1976, the astronomer S. Tapia discovered that light from the star is both linearly and circularly polarized, showing that there was a strong magnetic field surrounding the system and revealing that the system was more complex than previously thought.

Gamma Leporis, Latinized from γ Leporis, is a star in the south central part of the constellation Lepus, southeast of Beta Leporis and southwest of Delta Leporis. With an apparent visual magnitude of 3.587, it is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 112.02 mas as seen from Earth, its distance can be estimated as 29 light years from the Sun. It has a common proper motion companion, AK Leporis, which is a variable star of the BY Draconis type.

A planetary system and various minor objects such as asteroids, comets and debris, can form in a hierarchical process of accretion from the protoplanetary disks that surround newly formed stars. The various distinctive types of stars are shown by the Hertzsprung–Russell diagram (H–R diagram)—a plot of absolute stellar luminosity versus surface temperature. Each star follows an evolutionary track across this diagram. If this track takes the star through a region containing an intrinsic variable type, then its physical properties can cause it to become a variable star.

The primary, component A, is an F-type subgiant star with a stellar classification of F8 IV, a star that has exhausted its core hydrogen and is evolving to become a red giant. The star was once thought to be a BY Draconis variable with the variable star designation MQ Ser, but has been found not to be. From observations made between 1975 and 1980, Bakos (1983) reported random, small brightness variations with an amplitude of less than 0.03 magnitude, plus three flare events that increased the brightness by 0.1 magnitudes.

S Canis Minoris is a variable star in the equatorial constellation Canis Minor. It has a peak apparent visual magnitude of , which lies below the minimum brightness that is normally visible to the naked eye. The star is located at a distance of approximately 1,600 light-years from the Sun based on stellar parallax, and is drifting further away with a radial velocity of about +68 km/s. This is an aging red giant star with a stellar classification of M7-8e, where the 'e' suffix indicates emission lines in the spectrum.

Psi Phoenicis (ψ Phoenicis) is a star in the constellation Phoenix. Its apparent magnitude varies from 4.3 to 4.5 with a period of about 30 days and it is approximately 342 light years away based on parallax. Psi Phoenicis is a red giant in the asymptotic branch with a spectral type of M4III, indicating it is an evolved star in the last evolutionary stage before becoming a white dwarf. In 1973 astronomer Olin J. Eggen discovered it is a variable star, varying in magnitude between 4.3 and 4.5 with an approximate period of 30 days.

Combining light curves with spectral data often gives a clue as to the changes that occur in a variable star. For example, evidence for a pulsating star is found in its shifting spectrum because its surface periodically moves toward and away from us, with the same frequency as its changing brightness. About two-thirds of all variable stars appear to be pulsating. In the 1930s astronomer Arthur Stanley Eddington showed that the mathematical equations that describe the interior of a star may lead to instabilities that cause a star to pulsate.

UX Antliae is post-AGB star. It is an R Coronae Borealis variable star that has a base apparent magnitude of around 11.85, with irregular dimmings down to below magnitude 18.0. Researchers David Kilkenny and J.E. Westerhuys of the South African Astronomical Observatory confirmed that UX Antliae was an R Coronae Borealis variable in 1990 after noting the similarity of its spectrum to the RCB star W Mensae. It had been suspected of being one since 1940, but had been little-studied and exhibited no characteristic declines between 1975 and 1990.

Lambda Ursae Minoris (λ UMi, λ Ursae Minoris) is a star in the constellation Ursa Minor. It is an M-type red giant with an apparent magnitude of +6.38 and is approximately 880 light years from Earth. Lambda Ursae Minoris is an asymptotic giant branch (AGB) star, a star that has exhausted its core hydrogen and helium and is now fusing material in shells outside its core. AGB stars are often unstable and tend to pulsate, and Lambda Ursae Minoris is classified as a semiregular variable star and its brightness varies by about 0.1 magnitudes.

The star's variability was first recorded in 1888 by H.M. Paul,. At the time, it had the shortest known period of any variable star. It was initially thought to be an Algol- type eclipsing binary, but this was discounted by E.C. Pickering on account of it lacking a shallow minimum in its maximum and the width of its minimum period. Alfred H. Joy noted the similarity of its light curve to W Ursae Majoris in 1926, concluding the system was indeed an eclipsing binary with two stars of spectral type A8.

The shapes of variable star light curves give valuable information about the underlying physical processes producing the brightness changes. For eclipsing variables, the shape of the light curve indicates the degree of totality, the relative sizes of the stars, and their relative surface brightnesses. It may also show the eccentricity of the orbit and distortions in the shape of the two stars. For pulsating stars, the amplitude or period of the pulsations can be related to the luminosity of the star, and the light curve shape can be an indicator of the pulsation mode.

In 1932, Parenago began studies of the structure and kinematics of the Milky Way based primarily on star data. He and a colleague, B.V. Kukarkin, began an extensive compilation of variable star data. During his studies, Parenago observed approximately 3,000 stars in the Orion nebula region of the galaxy, the nearest star creating region to the Sun. Parenago then assumed a post at Moscow University as reader in stellar astronomy, becoming the first person to teach a lecture course on the subject of galactic astronomy in the Soviet Union in 1934.

Because of its northern declination, Auriga is only visible in its entirety as far as 34° south; for observers farther south it lies partially or fully below the horizon. A large constellation, with an area of 657 square degrees, it is half the size of the largest, Hydra. Its brightest star, Capella, is an unusual multiple star system among the brightest stars in the night sky. Beta Aurigae is an interesting variable star in the constellation; Epsilon Aurigae, a nearby eclipsing binary with an unusually long period, has been studied intensively.

Omicron Serpentis (ο Ser, ο Serpentis) is a solitary star in the Serpens Cauda (tail) section of the equatorial constellation Serpens. Based upon an annual parallax shift of 18.83 mas as seen from Earth, it is located around 173 light years from the Sun. The star is visible to the naked eye with a base apparent visual magnitude of +4.26. This is a white-hued A-type main sequence star with a stellar classification of A2 Va. It is located on the lower instability strip and is classified as a Delta Scuti type variable star.

The star system is one of the few eclipsing symbiotic binaries, but is unusual because the secondary star is not a white dwarf, but an A-type star. DY Persei is a variable star that is the prototype of DY Persei variables, which are carbon-rich R Coronae Borealis variables that exhibit the variability of asymptotic giant branch stars. DY Persei itself is a carbon star that is too dim to see through binoculars, with an apparent magnitude of 10.6. Seven stars in Perseus have been found to have planetary systems.

The stellar classification assigned to this star is A6 V, which indicates it is an A-type main-sequence star that is generating energy through hydrogen fusion at its core. The star's variability was first noticed by American astronomer Frank Schlesinger in 1914 and it has been given the variable star designation DD UMa. This is a low amplitude Delta Scuti variable with a magnitude change of around 0.4 and pulsation cycles of 9.4 and 15.0 cycles per day. It is rotating rapidly with a projected rotational velocity of about 158 km/s.

The brighter magnitude 5.18 primary is an aging red giant star with a stellar classification of M1IIIab. Having exhausted the supply of hydrogen at its core, it has expanded to around 45 times the radius of the Sun. It is a suspected variable star of unknown type and amplitude. The star is radiating 439 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,954 K. An optical companion, with a spectral type of K, is a few arcseconds away and has an apparent magnitude of 10.14.

Zeta Crateris is a confirmed member of the Sirius supercluster and is a candidate member of the Ursa Major Moving Group, a collection of stars that share a similar motion through space and may have at one time been members of the same open cluster. The system is located 326 ± 9 light-years from the Sun. Variable stars are popular targets for amateur astronomers, their observations providing valuable contributions to understanding star behaviour. Located near Alkes is the red-hued R Crateris, a semiregular variable star of type SRb and a spectral classification of M7.

Flanking Alpha to the east is Gamma Coronae Borealis, yet another binary star system, whose components orbit each other every 92.94 years and are roughly as far apart from each other as the Sun and Neptune. The brighter component has been classed as a Delta Scuti variable star, though this view is not universal. The components are main sequence stars of spectral types B9V and A3V. Located 170±2 light-years away, 4.06-magnitude Delta Coronae Borealis is a yellow giant star of spectral type G3.5III that is around and has swollen to .

The visible component is an aging red giant star on the asymptotic giant branch with a stellar classification of M1III, indicating it has exhausted the supply of both hydrogen and helium at its core and is cooling and expanding. It is a suspected variable star of unknown type that has been measured ranging in brightness from visual magnitude 4.94 down to 5.07. At present it has 48 times the radius of the Sun. It is radiating 502 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,948 K.

Fabricius discovered the first known periodic variable star (as opposed to cataclysmic variables, such as novas and supernovas), Mira, in August 1596. At first he believed it to be "just" another nova, as the whole concept of a recurring variable did not exist at the time. When he saw Mira brighten again in 1609, however, it became clear that a new kind of object had been discovered in the sky. Two years later, his son Johannes Fabricius (1587–1615) returned from university in the Netherlands with telescopes that they turned on the Sun.

This is an aging red giant with a stellar classification of M6 III, currently on the asymptotic giant branch. It is a semiregular variable star of sub-type SRb that ranges in magnitude from 4.91 down to 5.26 with a period of 60 days. The star has expanded to 204 times the Sun's radius and is radiating 7,412 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,516 K. Far-ultraviolet emission has been detected from these coordinates, which may be coming from a companion star.

S Cassiopeiae has a radius of 934 solar radii; if placed at the center of the Solar System, it would extend past the orbit of Mars and the Asteroid Belt. Its effective temperature is 1,800 K, which is exceptionally cool for any star, and its bolometric luminosity is 5,210 times that of the sun. S Cassiopeiae is a variable Mira, a pulsating variable star whose visual brightness varies over several magnitudes with a somewhat regular period and amplitude. Its visual magnitude varies between +7.9 and +16.1 over an average period of 612.43 days.

AZ Canis Minoris is a variable star in the equatorial constellation of Canis Minor. It is just visible to the naked eye in good viewing conditions as a dim, white-hued star with an apparent visual magnitude of around 6.46. The star is located around 500 light years away from the Sun based on parallax, and is drifting further away with a radial velocity of +15 km/s. No evidence has been found for a companion to this star, although in the past it has been reported as a binary star system.

Theta Herculis is a single, variable star in the northern constellation of Hercules. This object is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 3.851. Based upon parallax measurements, it is located around 750 light years away from the Sun. The star is advancing toward the Earth with a heliocentric radial velocity of –28 km/s. This is an aging K-type bright giant with a stellar classification of K1IIaCN2, where the suffix notation indicates a strong overabundance of CN in the spectrum.

An AM Canum Venaticorum star (AM CVn star), is a rare type of cataclysmic variable star named after their type star, AM Canum Venaticorum. In these hot blue binary variables, a white dwarf accretes hydrogen-poor matter from a compact companion star. These binaries have extremely short orbital periods (shorter than about one hour) and have unusual spectra dominated by helium with hydrogen absent or extremely weak. They are predicted to be strong sources of gravitational waves, strong enough to be detected with the Laser Interferometer Space Antenna (LISA).

This is a magnetic chemically peculiar star, or Ap star, with a stellar classification of F0VpSrCrEu, matching an F-type main-sequence star with abundance anomalies of strontium, chromium, and europium in the spectrum. It is a variable star of type Alpha2 Canum Venaticorum that ranges in visual magnitude from 5.61 down to 5.67 with a period of 223.826 days. This is most likely the mean rotational period of the star. V1291 Aquilae was one of the first Ap stars discovered with a period of more than 100 days.

Gliese 54 (GJ 54 / HIP 5496 / LHS 1208) is a star near the Solar System located at 25.7 light years away. It is located in the constellation of Tucana, close to the edge, almost in the neighboring Hydrus. It is below the threshold brightness to be observable eye with an apparent magnitude of +9.80,. Gliese 54 is a red dwarf of spectral type M2 with an effective temperature of 4250 K. In the SIMBAD database it appears listed as variable star, getting the provisional variable designation NSV 427.

NGC 6940 has hundreds of members. The cluster is quite scattered and in between its members are also visible field stars. For example, two bright stars, an 8.6 mag B8III giant star at the NE edge and a 9.1 mag A0III giant at the SW corner of the cluster are too young to be true members of NGC 6940 and are probably background stars. The brightest star (lucida) of NGC 6940 is the red giant VG Vulpeculae, a semiregular variable star whose magnitude ranges from 9.0 to 9.5 every 80 days approximately.

EX Hydrae is a variable star classified as an eclipsing intermediate polar- type cataclysmic variable, specifically of the DQ Herculis type. The system varies in apparent magnitude from 9.6 to 14.locator chart at AAVSO The system consists of a white dwarf primary and an M-type secondary, of masses of and respectively.Beuermann, K., Harrison, T.E., MacArthur, B.E., Benedict, G.F., & Gansicke, B.T., 2003, "A Precise HST Parallax of the Cataclysmic Variable EX Hydrae, its System Parameters, and Accretion Rate," A&A; 412, 821, abstract available online here The orbital period is 98.25696 minutes (0.068233846 days).

The stellar classification of the visible component is A3 IVs, which matches an A-type subgiant star with narrow absorption lines. It is a suspected chemically peculiar star that is about of the way through its main sequence lifetime. SIMBAD lists this star as a variable star, although it is not catalogued as such in the GCVS. It has more than double the mass and radius of the Sun, and is radiating 35 times the Sun's luminosity from its photosphere at an effective temperature of around 9,355 K.

The primary member of this system, component A, is an evolved red giant star, currently on the asymptotic giant branch, with a stellar classification of M2− IIIab. It is a suspected variable star of unknown type with a brightness that varies from visual magnitude 4.95 down to 5.00. As of 2011, the magnitude 9.88 secondary, component B, lay at an angular separation of along a position angle of 226° relative to the primary. In the sky, the open cluster Messier 52 is 40' to the south of it, near the constellation border with Cepheus.

Because this star is positioned near the ecliptic, it is subject to lunar eclipses. This object is an aging red giant star currently on the asymptotic giant branch with a stellar classification of M2 III, having exhausted both the hydrogen and helium at its core and expanded to 56 times the Sun's radius. It is a suspected variable star of unknown type that ranges in magnitude between 6.24 and 6.29. The star is radiating 693 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 3,946 K.

A stellar classification of G6 III indicates this is an evolved giant star, most likely (98% chance) on the horizontal branch, having exhausted the hydrogen at its core and expanded. It is a suspected variable star of unknown type. 44 Aquarii is 537 million years old with about 2.53 times the mass of the Sun and 9 times the Sun's radius. The star is radiating 62 times the Sun's luminosity from its photosphere at an effective temperature of 5,025 K. At this heat, the star has the golden-hued glow of a G-type star.

The spectrum of this star matches a stellar classification of B1.5 IV, which indicates this star has entered the subgiant stage and is in the process of evolving into a giant star. It is radiating around 10,000 times the luminosity of the Sun from its outer atmosphere at an effective temperature of 23,000 K, giving it a blue-white hue. This star has nearly 12 times the mass of the Sun and is roughly 15 million years old. Delta Lupi is a Beta Cephei variable star that undergoes periodic pulsations.