Gamma2 Octantis
Star in the constellation Octans
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γ2 Octantis, Latinized to Gamma2 Octantis (Gamma2 Oct), is a solitary[12] star in the southern circumpolar constellation Octans. It has an apparent magnitude of 5.72,[2] allowing it to be faintly seen with the naked eye. Parallax measurements place the object at a distance of 320 light years[1] and is currently receding with a heliocentric radial velocity of 27 km/s.[6]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Octans |
| Right ascension | 23h 57m 32.8617s[1] |
| Declination | −82° 10′ 11.310″[1] |
| Apparent magnitude (V) | 5.72±0.01[2] |
| Characteristics | |
| Evolutionary stage | red clump[3] |
| Spectral type | K0 III[4] |
| U−B color index | +0.92[5] |
| B−V color index | +1.05[5] |
| Astrometry | |
| Radial velocity (Rv) | 27.2±2.9[6] km/s |
| Proper motion (μ) | RA: −22.246 mas/yr[1] Dec.: −23.235 mas/yr[1] |
| Parallax (π) | 10.1771±0.0345 mas[1] |
| Distance | 320 ± 1 ly (98.3 ± 0.3 pc) |
| Absolute magnitude (MV) | +0.87[7] |
| Details[8] | |
| Mass | 1.15±0.15 M☉ |
| Radius | 10.54±0.28 R☉ |
| Luminosity | 52.6±1.3 L☉ |
| Surface gravity (log g) | 2.53±0.13 cgs |
| Temperature | 4,788±58 K |
| Metallicity [Fe/H] | −0.04±0.04 dex |
| Rotational velocity (v sin i) | 2.8±1.1[9] km/s |
| Other designations | |
| γ2 Oct, 87 G. Octantis, CPD−82°907, HD 224362, HIP 118114, HR 9061, SAO 258996[10][11] | |
| Database references | |
| SIMBAD | data |
Gamma2 Oct has a stellar classification of K0 III,[4] indicating that it is a red giant. At present it has 115% the mass of the Sun but has expanded to 10.54 times its girth.[8] It shines at 52.6 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,788 K,[8] giving it a yellow-orange glow. Gamma2 Oct has a metallicity around 91% that of the Sun[8] and spins with a projected rotational velocity of about 3 km/s.[9]