Omicron2 Centauri
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 11h 31m 48.79955s |
| Declination | −59° 30′ 56.3296″ |
| Apparent magnitude (V) | +5.14 (5.12 - 5.22) |
| Characteristics | |
| Evolutionary stage | Blue supergiant |
| Spectral type | A2Iae |
| U−B color index | −0.11 |
| B−V color index | +0.49 |
| Variable type | α Cyg |
| Astrometry | |
| Radial velocity (Rv) | −16.8 km/s |
| Proper motion (μ) | RA: −6.976 mas/yr Dec.: +1.118 mas/yr |
| Parallax (π) | 0.4665±0.0713 mas |
| Distance | approx. 7,000 ly (approx. 2,100 pc) |
| Absolute magnitude (MV) | −7.50 |
| Details | |
| Mass | 18 M☉ |
| Radius | 131 R☉ |
| Luminosity | 105,000 L☉ |
| Surface gravity (log g) | 1.46 cgs |
| Temperature | 9,080 K |
| Rotation | 132 days |
| Rotational velocity (v sin i) | 50 km/s |
| Other designations | |
| ο2 Cen, CD−58°4101, FK5 2920, GC 15820, HD 100262, HIP 56250, HR 4442, SAO 239146 | |
| Database references | |
| SIMBAD | data |
Omicron2 Centauri is a star in the southern constellation Centaurus. Its name is a Bayer designation that is Latinied from ο2 Centauri, and abbreviated Omicron2 Cen or ο2 Cen. This star is visible to the naked eye with a mean apparent visual magnitude of +5.12. Based on parallax measurements, it is located at a distance of approximately 7,000 light years from Earth.
ο2 Centauri is a white A-type blue supergiant. It is classified as an Alpha Cygni type variable star and its brightness varies from magnitude +5.12 to +5.22 with a period of 46.3 days. In 1996, Kaufer and colleagues calculated Omicron2 Centauri to be around 136,000 times as luminous, 18 times as massive and have 131 times the diameter of the Sun.
ο2 Cen forms a close naked eye pair with ο1 Cen, another 5th magnitude supergiant (possibly a yellow hypergiant). Both stars are located between Crux (the Southern Cross) and the brightest yellow hypergiant in the sky, V382 Carinae.