HD 15920

HD 15920 is a single^[7] star in the northern constellation of Cassiopeia. It has a yellow hue and is visible to the naked eye as a dim point of light with an apparent visual magnitude of 5.17.^[1] This object is located at a distance of approximately 269 light years from the Sun based on parallax, but it is drifting closer with a radial velocity of −4 km/s.^[2]

HD 15920

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Cassiopeia[1]
Right ascension	02h 38m 02.03317s[2]
Declination	+72° 49′ 05.7106″[2]
Apparent magnitude (V)	5.17[1]
Characteristics
Evolutionary stage	red giant branch[2]
Spectral type	G8III[3]
B−V color index	+0.896±0.003[1]
Astrometry
Radial velocity (Rv)	−3.81±0.12[2] km/s
Proper motion (μ)	RA: −27.072[2] mas/yr Dec.: +15.618[2] mas/yr
Parallax (π)	12.1337±0.0717 mas[2]
Distance	269 ± 2 ly (82.4 ± 0.5 pc)
Absolute magnitude (MV)	0.70[1]
Details
Mass	2.55±0.68[4] M☉
Radius	10.26±0.73[5] R☉
Luminosity	64+6 −5[5] L☉
Surface gravity (log g)	2.91±0.11[4] cgs
Temperature	5,104±148[5] K
Metallicity [Fe/H]	0.02±0.05[4] dex
Age	977+198 −164[4] Myr
Other designations
BD+72°140, FK5 87, GC 3116, HD 15920, HIP 12273, HR 743, SAO 4694, GSC 04320-02109[6]
Database references
SIMBAD	data

This object is an aging giant star with a stellar classification of G8III.^[3] After exhausting the supply of hydrogen at its core, this star has cooled and expanded off the main sequence – at present it has ten times the girth of the Sun.^[5] The star is around a billion years old with 2.6 times the mass of the Sun.^[4] It is radiating 64 times the Sun's luminosity from its swollen photosphere at an effective temperature of 5,104 K.^[5] HD 15920 is the most likely source for the X-ray emission detected at these coordinates.^[8]