S Carinae
Star in the constellation Carina
From Wikipedia, the free encyclopedia
S Carinae (HD 88366) is a variable star in the constellation Carina, approximately 1,620 light years from Earth.
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Carina |
| Right ascension | 10h 09m 21.894s[1] |
| Declination | −61° 32′ 56.43″[1] |
| Apparent magnitude (V) | 4.5 - 10.0[2] |
| Characteristics | |
| Evolutionary stage | AGB[3] |
| Spectral type | K5e - M6e[2] |
| U−B color index | +0.93 to +1.93[4] |
| B−V color index | +1.43 to +2.60[4] |
| Variable type | Mira[2] |
| Astrometry | |
| Radial velocity (Rv) | 289.30[5] km/s |
| Proper motion (μ) | RA: −94.237[1] mas/yr Dec.: 76.811[1] mas/yr |
| Parallax (π) | 2.0110±0.0855 mas[1] |
| Distance | 1,620 ± 70 ly (500 ± 20 pc) |
| Absolute magnitude (MV) | −0.71 to −3.41[6] |
| Details | |
| Mass | 0.6[7] M☉ |
| Radius | 120[7] R☉ |
| Luminosity | 2,200[4] L☉ |
| Surface gravity (log g) | −0.9 - 1.0[8] cgs |
| Temperature | 3,050 - 3,590[8] K |
| Other designations | |
| HR 3999, HD 88366, CP−60°1701, HIP 49751, SAO 250840, GC 13971 | |
| Database references | |
| SIMBAD | data |
S Carinae is an M-type red giant. Benjamin Apthorp Gould discovered the variable star, in 1871. It appeared with its variable star designation, S Carinae, in Annie Jump Cannon's 1907 work, Second Catalogue of Variable Stars.[10] 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.[2] When it is near its maximum brightness, it is visible to the naked eye. It has one of the earliest spectral types, and hence the hottest temperatures, of any Mira variable, and has a relatively short period for the class.[11] The temperature of this pulsing star is highest at visual brightness maximum and lowest at visual brightness minimum.[8]
S Carinae has exhausted its core hydrogen and expanded to become a red giant. It has also exhausted its core helium and evolved to the asymptotic giant branch, where it fuses hydrogen and helium in separate shells outside the core.[11][3]