HD 85951
Star in the constellation of Hydra
From Wikipedia, the free encyclopedia
HD 85951 (HR 3923), formally named Felis /ˈfiːlɪs/,[13] is a solitary[14] orange-hued star in the constellation Hydra. It has an apparent magnitude of 4.94,[3] making it faintly visible to the naked eye under ideal conditions. Based on parallax measurements, the object is about 570 light-years away from the Sun[2] and is receding with a heliocentric radial velocity of 50 km/s.[6]
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Hydra[1] |
| Right ascension | 09h 54m 52.2045s[2] |
| Declination | −19° 00′ 33.620″[2] |
| Apparent magnitude (V) | 4.94[3] |
| Characteristics | |
| Evolutionary stage | AGB[4] |
| Spectral type | K5 III[5] |
| U−B color index | +1.93[3] |
| B−V color index | +1.57[3] |
| Astrometry | |
| Radial velocity (Rv) | 50±4.2[6] km/s |
| Proper motion (μ) | RA: −45.386 mas/yr[2] Dec.: −40.456 mas/yr[2] |
| Parallax (π) | 5.6789±0.2214 mas[2] |
| Distance | 570 ± 20 ly (176 ± 7 pc) |
| Absolute magnitude (MV) | −1.43[1] |
| Details | |
| Mass | 6.40+1.2 −0.4[7] M☉ |
| Radius | 56.7[8] R☉ |
| Luminosity | 721±32[9] L☉ |
| Surface gravity (log g) | 1.3±0.04[10] cgs |
| Temperature | 3,875±39[10] K |
| Metallicity [Fe/H] | −0.18±0.07[10] dex |
| Other designations | |
| Felis, 183 G. Hydrae[11], BD−18°2810, FK5 373, GC 13644, HD 85951, HIP 48615, HR 3923, SAO 155588[12] | |
| Database references | |
| SIMBAD | data |
Nomenclature
HD 85951 was the brightest star in the now-obsolete constellation of Felis, and was designated c Felis in Bode's star chart.[15] In 2016, the IAU organized a Working Group on Star Names (WGSN)[16] to catalog and standardize proper names for stars. The WGSN approved the name Felis for this star on 1 June 2018 and it is now so included in the List of IAU-approved Star Names.[13]
Properties
HD 85951 is an evolved red giant with a stellar classification of K5 III.[5] It is currently on the asymptotic giant branch,[4] generating energy via fusion of hydrogen and helium shells around an inert carbon core. At present, Felis has 6.4 times the mass of the Sun[7] and, due to its evolved status, has an enlarged radius of 56.7 R☉.[8] It radiates at a bolometric luminosity 721 times that of the Sun[9] from its photosphere at an effective temperature of 3,875 K.[10] Felis has an iron abundance 66% that of the Sun, making it metal deficient.