Gamma Horologii

γ Horologii, Latinised as Gamma Horologii, is a solitary^[7] star in the southern constellation of Horologium. It is just bright enough to be visible to the naked eye as a dim, yellow-hued point of light with an apparent visual magnitude of +5.74.^[2] This object is located at a distance of 183 light years from the Sun, but is drifting closer with a radial velocity of −19 km/s.^[1]

Gamma Horologii

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Horologium
Right ascension	02h 45m 27.47800s[1]
Declination	−63° 42′ 16.3925″[1]
Apparent magnitude (V)	+5.743[2]
Characteristics
Spectral type	G8 III/IV[3]
B−V color index	+0.929[2]
Astrometry
Radial velocity (Rv)	−18.79±0.16[1] km/s
Proper motion (μ)	RA: +18.913[1] mas/yr Dec.: −8.742[1] mas/yr
Parallax (π)	17.7941±0.0592 mas[1]
Distance	183.3 ± 0.6 ly (56.2 ± 0.2 pc)
Absolute magnitude (MV)	+1.99[4]
Details
Radius	5.50+0.11 −0.08[1] R☉
Luminosity	16.9±0.1[1] L☉
Surface gravity (log g)	3.18±0.05[5] cgs
Temperature	4,961±24[5] K
Metallicity [Fe/H]	−0.26±0.02[5] dex
Other designations
γ Hor, CPD−64°196, HD 17504, HIP 12871, HR 833, SAO 248642, WDS J02455-6342A[6]
Database references
SIMBAD	data

The stellar classification of this object is G8 III/IV,^[3] matching a G-type star with a luminosity class intermediate between a subgiant and giant star. This suggests it has exhausted the supply of hydrogen at its core and is evolving off the main sequence. It has 5.5^[1] times the radius of the Sun and is radiating 17^[1] times the Sun's luminosity from its swelling photosphere at an effective temperature of 4,961 K.^[5] The metallicity is sub-solar,^[5] indicating a lower abundance of elements more massive than helium, as compared to the Sun.