HD 81101

This article is about k Carinae. For K Carinae, see HR 4138.

HD 81101 is a single^[7] star in the southern constellation of Carina. It has the Bayer designation k Carinae, while HD 81101 is the star's designation in the Henry Draper catalogue. The star has a yellow hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.79.^[2] It is located at a distance of approximately 225 light years from the Sun based on parallax.^[1] This object is drifting further away with a radial velocity of +51 km/s,^[1] having come to within 22 light-years of the Sun some 1.4 million years ago.^[8]

HD 81101

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Carina
Right ascension	09h 20m 56.81329s[1]
Declination	−62° 24′ 16.6811″[1]
Apparent magnitude (V)	4.79[2]
Characteristics
Spectral type	G6III[3]
B−V color index	+0.926±0.035[2]
Astrometry
Radial velocity (Rv)	+51.12±0.15[1] km/s
Proper motion (μ)	RA: −27.15[1] mas/yr Dec.: −14.18[1] mas/yr
Parallax (π)	14.4946±0.1593 mas[1]
Distance	225 ± 2 ly (69.0 ± 0.8 pc)
Absolute magnitude (MV)	0.51[2]
Details
Mass	1.95[4] M☉
Radius	11.19+0.19 −0.15[1] R☉
Luminosity	65.4±0.9[1] L☉
Surface gravity (log g)	2.720±0.050[5] cgs
Temperature	4,908+43 −33[1] K
Metallicity [Fe/H]	−0.360±0.020[5] dex
Age	2.04[4] Gyr
Other designations
k Car, CPD−61°1242, FK5 2745, GC 12923, HD 81101, HIP 45856, HR 3728, SAO 250544[6]
Database references
SIMBAD	data

This is an aging giant star with a stellar classification of G6III,^[3] having exhausted the supply of hydrogen at its core then cooled and expanded away from the main sequence. It is two^[4] billion years old with 1.95^[4] times the mass of the Sun and has expanded to 11^[1] times the Sun's radius. The star is radiating 65^[1] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,908 K.^[1] Being a member of the old disk population,^[9] the metallicity of the star's stellar atmosphere is much lower than solar.^[5]