Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Perseus |
Right ascension | 2h 22m 24.296s [1] |
Declination | +57° 06′ 34.10″ [1] |
Apparent magnitude (V) | 7.82-10.0 [2] |
Characteristics | |
Evolutionary stage | Red supergiant |
Spectral type | M4Iab [3] |
Variable type | SRc [2] |
Astrometry | |
Radial velocity (Rv) | −38.0±2 [4] km/s |
Proper motion (μ) | RA: −0.602 [1] mas/yr Dec.: −1.107 [1] mas/yr |
Parallax (π) | 0.3874 ± 0.0450 mas [1] |
Distance | 4,880+720 −561 ly (1,497+221 −172 pc) [5] |
Absolute magnitude (MV) | −6.18 [6] |
Details | |
Mass | 12 –15 [7] M☉ |
Radius | 547+9 −7 [5] –775+110 −85 [8] R☉ |
Luminosity | 59,000 [9] L☉ |
Surface gravity (log g) | −0.2±0.05 [7] cgs |
Temperature | 3,470±90 [7] K |
Other designations | |
Database references | |
SIMBAD | data |
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.
RS Persei is a member of the cluster NGC 884, χ Persei, one half of the famous Double Cluster. [10]
In March of 1904, Lidiya Tseraskaya discovered that the star, then called BD +56°583, is a variable star. [12] It was listed with its variable star designation, RS Persei, in Annie Jump Cannon's 1907 work Second Catalog of Variable Stars. [13] RS Persei is classified as a semiregular variable star, with its brightness varying from magnitude 7.82 to 10.0 over 245 days, [2] Detailed studies show that it also pulsates with a long secondary period of 4,200±1,500 days. [14]
RS Persei is a large cool star with a temperature of 3,500 K. This makes it luminous, although much of its radiation is emitted in the infrared. In 2005, RS Per was calculated to have a bolometric luminosity of 145,000 L☉ and a radius around 1,000 R☉. [6] More recently, 2014 calculations across all wavelengths gives the star a lower luminosity of 77,600+9,500
−8,400 L☉ based on an assumed distance, and a radius of 770±30 R☉ based on the measured angular diameter and luminosity. [7] A 2023 paper gives an even smaller luminosity of 59,000 L☉. [9]
The angular diameter of RS Persei was measured at 3.4±0.03 mas . At a distance of 1,497 parsecs, this corresponds to a radius of 547 R☉. [5] Another paper from the same author gives 3.34+0.07
−0.09 mas and a radius of 775 R☉, altought the distance used isn't is mentioned. [8] It is surrounded by dust that has condensed from material lost by the star. [15]
RS Persei has sometimes been considered to be a highly evolved low mass Asymptotic Giant Branch (AGB) star, [16] but calculations of its current mass suggest that it is a true red supergiant. NGC 244 is also too young to host AGB stars. [7]
Red supergiants (RSGs) are stars with a supergiant luminosity class and a stellar classification K or M. They are the largest stars in the universe in terms of volume, although they are not the most massive or luminous. Betelgeuse and Antares A are the brightest and best known red supergiants (RSGs), indeed the only first magnitude red supergiant stars.
A blue supergiant (BSG) is a hot, luminous star, often referred to as an OB supergiant. They are usually considered to be those with luminosity class I and spectral class B9 or earlier, although sometimes A-class supergiants are also deemed blue supergiants.
Mu Cephei, also known as Herschel's Garnet Star, Erakis, or HD 206936, is a red supergiant or hypergiant star in the constellation Cepheus. It appears garnet red and is located at the edge of the IC 1396 nebula. It is a 4th magnitude star easily visible to the naked eye under good observing conditions. Since 1943, the spectrum of this star has served as a spectral standard by which other stars are classified.
KY Cygni is a red supergiant of spectral class M3.5Ia located in the constellation Cygnus. It is approximately 4,700 light-years away.
Phi Cassiopeiae is a multiple star in the constellation Cassiopeia with a combined apparent magnitude of +4.95. The two brightest components are A and C, sometimes called φ1 and φ2 Cas. φ Cas A is an F0 bright supergiant of magnitude 4.95 and φ Cas C is a 7.08 magnitude B6 supergiant at 134".
A yellow hypergiant (YHG) is a massive star with an extended atmosphere, a spectral class from A to K, and, starting with an initial mass of about 20–60 solar masses, has lost as much as half that mass. They are amongst the most visually luminous stars, with absolute magnitude (MV) around −9, but also one of the rarest, with just 20 known in the Milky Way and six of those in just a single cluster. They are sometimes referred to as cool hypergiants in comparison with O- and B-type stars, and sometimes as warm hypergiants in comparison with red supergiants.
V354 Cephei is a red supergiant star located within the Milky Way. It is an irregular variable located over 13,000 light-years away from the Sun. It has an estimated radius of 1,139 solar radii. If it were placed in the center of the Solar System, it would extend to between the orbits of Mars and Jupiter.
MY Cephei is a red supergiant located in open cluster NGC 7419 in the constellation of Cepheus. It is a semiregular variable star with a maximum brightness of magnitude 14.4 and a minimum of magnitude 15.5.
S Persei is a red supergiant or hypergiant located near the Double Cluster in Perseus, north of the cluster NGC 869. It is a member of the Perseus OB1 association and one of the largest known stars. If placed in the Solar System, its photosphere would engulf the orbit of Jupiter. It is also a semiregular variable, a star whose variations are less regular than those of Mira variables.
NO Aurigae is a pulsating variable star in the constellation Auriga. It is an unusually-luminous asymptotic giant branch star about 3,500 light years away. It is a 6th magnitude star faintly visible to the naked eye under very good observing conditions.
WOH G64 is an unusual yellow hypergiant star in the Large Magellanic Cloud (LMC) satellite galaxy in the southern constellation of Dorado.
A hypergiant (luminosity class 0 or Ia+) is a very rare type of star that has an extremely high luminosity, mass, size and mass loss because of its extreme stellar winds. The term hypergiant is defined as luminosity class 0 (zero) in the MKK system. However, this is rarely seen in literature or in published spectral classifications, except for specific well-defined groups such as the yellow hypergiants, RSG (red supergiants), or blue B(e) supergiants with emission spectra. More commonly, hypergiants are classed as Ia-0 or Ia+, but red supergiants are rarely assigned these spectral classifications. Astronomers are interested in these stars because they relate to understanding stellar evolution, especially star formation, stability, and their expected demise as supernovae. Notable examples of hypergiants include the Pistol Star, a blue hypergiant located close to the Galactic Center and one of the most luminous stars known; Rho Cassiopeiae, a yellow hypergiant that is one of the brightest to the naked eye; and Mu Cephei (Herschel's "Garnet Star"), one of the largest and brightest stars known.
V602 Carinae is a red supergiant and variable star of spectral type M3 in the constellation Carina. It is considered to be one of largest known stars, being around 1,000 times larger than the Sun.
10 Persei is a blue supergiant star in the constellation Perseus. Its apparent magnitude is 6.26 although it is slightly variable.
T Persei is a red supergiant located in the constellation Perseus. It varies in brightness between magnitudes 8.3 and 9.7 and is considered to be a member of the Double Cluster.
V520 Persei is a blue supergiant member of NGC 869, one of the Perseus Double Cluster open clusters. It is an irregular variable star. At a magnitude of 6.55, V520 Persei is the brightest member in either NGC 869 or NGC 884, although the brighter HD 13994 lies in the foreground along the same line of sight.
BC Cygni is a red supergiant and pulsating variable star of spectral type M3.5Ia in the constellation Cygnus.
XX Persei is a semiregular variable red supergiant star in the constellation Perseus, between the Double Cluster and the border with Andromeda.
NGC 7419 is an open cluster in the constellation Cepheus. It is heavily reddened and notable for containing five red supergiants, the highest number known in any cluster until the end of the 20th century, but probably no blue supergiants.
Westerlund 1-243 or Wd 1-243 is a luminous blue variable (LBV) star undergoing an eruptive phase located within the outskirts of the super star cluster Westerlund 1. Located about 13,400 ly (4,100 pc) from Earth, it has a luminosity of 0.73 million L☉ making it one of the most luminous stars known.