Gamma1 Octantis

γ¹ Octantis

Location of γ1 Octantis (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Octans
Right ascension	23h 52m 06.47318s[1]
Declination	−82° 01′ 07.7636″[1]
Apparent magnitude (V)	5.10[2]
Characteristics
Evolutionary stage	red clump[3]
Spectral type	G7III[4]
U−B color index	+0.60[5]
B−V color index	+0.92[5]
Astrometry
Radial velocity (Rv)	+15.4±0.1[6] km/s
Proper motion (μ)	RA: −45.670[1] mas/yr Dec.: −15.666[1] mas/yr
Parallax (π)	12.1790±0.0552 mas[1]
Distance	268 ± 1 ly (82.1 ± 0.4 pc)
Absolute magnitude (MV)	0.55[2]
Details
Mass	1.81[7] M☉
Radius	10.3[8] R☉
Luminosity	60[8] L☉
Surface gravity (log g)	2.64[7] cgs
Temperature	5,017[8] K
Metallicity [Fe/H]	−0.34[9] dex
Rotational velocity (v sin i)	1.8[10] km/s
Other designations
γ1 Oct, 86 G. Octantis, CPD−82°905, FK5 3997, GC 33107, HD 223647, HIP 117689, HR 9032, SAO 258989[11][12]
Database references
SIMBAD	data

Gamma¹ Octantis, Latinized from γ¹ Octantis, is a single,^[13] yellow-hued star in the constellation which includes the southern celestial pole, Octans. Its apparent visual magnitude is 5.10,^[2] meaning that in good conditions it is bright enough to be faintly visible to the naked eye.

Based upon an annual parallax shift of 12.2 mas which is taken during opposing points of the Earth's orbit of the sun (with compensation for its eccentricity),^[1] the star is about 268 light years away. Its (proper) motion has a net vector at present of receding from the Sun, at +15.4 km/s.^[6]

This is an evolved G-type giant star with a stellar classification of G7 III.^[4] It is a red clump star,^[3] which means it is generating energy through helium fusion at its core. The star has an estimated 1.81 times the mass of the Sun^[7] and it has expanded to over 10 times the Sun's radius and is radiating 60 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 5,017 K.^[8]