Rho Centauri, Latinized from ρ Centauri, is a binary star[11] system in the southern constellation of Centaurus. It is visible to the naked eye as a blue-white hued point of light with a combined apparent visual magnitude of +3.97.[2] The system is located approximately 276 light years from the Sun based on parallax, and is drifting further away with a radial velocity of around +15 km/s.[5] It is a proper motion member of the Lower Centaurus–Crux sub-group in the Scorpius–Centaurus OB association, the nearest such association of co-moving massive stars to the Sun.[3]
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 12h 11m 39.12805s[1] |
| Declination | −52° 22′ 06.4067″[1] |
| Apparent magnitude (V) | +3.97[2] |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | B3 V[3] |
| U−B color index | −0.650[4] |
| B−V color index | −0.156±0.008[2] |
| Astrometry | |
| Radial velocity (Rv) | +15.0±4.1[5] km/s |
| Proper motion (μ) | RA: −43.741[1] mas/yr Dec.: −11.771[1] mas/yr |
| Parallax (π) | 11.8348 ± 0.3746 mas[1] |
| Distance | 276 ± 9 ly (84 ± 3 pc) |
| Absolute magnitude (MV) | −1.33[2] |
| Details | |
| Mass | 6.6±0.1[6] M☉ |
| Radius | 3.8[7] R☉ |
| Luminosity | 810.42[2] L☉ |
| Surface gravity (log g) | 3.95[8] cgs |
| Temperature | 19,500[8] K |
| Rotational velocity (v sin i) | 147[9] km/s |
| Age | 23.7±1.4[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The primary component of this system is a B-type main-sequence star with a stellar classification of B3 V.[3] It is about 24[6] million years old with a high rate of spin, showing a projected rotational velocity of 147 km/s.[9] It has 6.6[6] times the mass of the Sun and 3.8[7] times the Sun's radius. The star is radiating 810[2] times the luminosity of the Sun from its photosphere at an effective temperature of 19,500 K.[8]
The secondary companion is 1.1 magnitudes fainter than the primary, with a projected separation of 5.68 AU along a position angle of 19.72°, as of 2013.[11]