Tau Centauri
Star in the constellation Centaurus
From Wikipedia, the free encyclopedia
Tau Centauri is a solitary[11] star in the southern constellation of Centaurus. Its name is a Bayer designation that is Latinized from τ Centauri, and abbreviated Tau Cen or τ Cen. This star is visible to the naked eye with an apparent visual magnitude of +3.86.[3] The distance to this star, based upon an annual parallax shift of 24.3 mas,[2] is 131 light years. It makes a star system with Gamma Centauri at 98% probability, both separated by 1.7 ly (0.53 pc).[12]
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Centaurus[1] |
| Right ascension | 12h 37m 42.164s[2] |
| Declination | −48° 32′ 28.70″[2] |
| Apparent magnitude (V) | +3.86[3] |
| Characteristics | |
| Spectral type | A0 V[4] or A1 IVnn[5] |
| U−B color index | +0.04[3] |
| B−V color index | +0.06[3] |
| Astrometry | |
| Radial velocity (Rv) | +5.5±2.3[6] km/s |
| Proper motion (μ) | RA: −186.081 mas/yr[2] Dec.: −6.757 mas/yr[2] |
| Parallax (π) | 24.2953±0.53 mas[2] |
| Distance | 134 ± 3 ly (41.2 ± 0.9 pc) |
| Absolute magnitude (MV) | +0.83[1] |
| Details | |
| Mass | 2.31[7] M☉ |
| Radius | 2.7[8] R☉ |
| Luminosity | 39[8] L☉ |
| Surface gravity (log g) | 4.02±0.14[7] cgs |
| Temperature | 10,533±358[7] K |
| Rotational velocity (v sin i) | 296.8±3.8[9] km/s |
| Age | 132[7] Myr |
| Other designations | |
| τ Cen, CD−47°7745, HD 109787, HIP 61622, HR 4802, SAO 223560[10] | |
| Database references | |
| SIMBAD | data |
This is an A-type star with stellar classifications of A0 V[4] or A1 IVnn,[5] indicating it may be a main sequence star or a more evolved subgiant star. It is around 132 million years old[7] and is spinning rapidly with a projected rotational velocity of 296.8 km/s.[9] This is giving the star an oblate shape, with an estimated equatorial girth that is 30% larger than the polar radius.[13] The star has an estimated 2.3 times the mass of the Sun[7] and 2.7 times the Sun's radius.[8]