Gamma1 Octantis
Yellow-hued giant star in the constellation Octans
From Wikipedia, the free encyclopedia
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.
 | |
| 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 |
Distance and proper motion
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]
Characteristics
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]