HD 85951

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,^[2] 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^[1] and is receding with a heliocentric radial velocity of 50 km/s.^[5]

HD 85951

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Hydra
Right ascension	09h 54m 52.2045s[1]
Declination	−19° 00′ 33.620″[1]
Apparent magnitude (V)	4.94[2]
Characteristics
Evolutionary stage	AGB[3]
Spectral type	K5 III[4]
U−B color index	+1.93[2]
B−V color index	+1.57[2]
Astrometry
Radial velocity (Rv)	50±4.2[5] km/s
Proper motion (μ)	RA: −45.386 mas/yr[1] Dec.: −40.456 mas/yr[1]
Parallax (π)	5.6789±0.2214 mas[1]
Distance	570 ± 20 ly (176 ± 7 pc)
Absolute magnitude (MV)	−1.43[6]
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, 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.^[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

This an evolved red giant with a stellar classification of K5 III.^[4] It is currently on the asymptotic giant branch,^[3] 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.