Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Centaurus |
Right ascension | 11h 21m 00.41s[1] |
Declination | −54° 29′ 27.7″[1] |
Apparent magnitude (V) | +3.90[2] (4.08 + 5.65)[3] |
Characteristics | |
Spectral type | B5Vn[4] + B6V[5] |
B−V color index | −0.157±0.015[2] |
Astrometry | |
Radial velocity (Rv) | +9.4±3.7[2] km/s |
Proper motion (μ) | RA: −35.85±0.34[1] mas/yr Dec.: −1.72±0.27[1] mas/yr |
Parallax (π) | 9.12 ± 0.34 mas[1] |
Distance | 360 ± 10 ly (110 ± 4 pc) |
Absolute magnitude (MV) | −1.30[2] |
Orbit[6] | |
Period (P) | 39.0±0.19 yr |
Semi-major axis (a) | 0.2263±0.0011″ |
Eccentricity (e) | 0.8530±0.0040 |
Inclination (i) | 19.4±4.9° |
Longitude of the node (Ω) | 327.8±3.9° |
Periastron epoch (T) | 2010.410±0.037 |
Argument of periastron (ω) (secondary) | 340.3±4.0° |
Details | |
A | |
Mass | 6.43[6] M☉ |
Temperature | 16,760[7] K |
Rotational velocity (v sin i) | 340[8] km/s |
B | |
Mass | 3.68[6] M☉ |
Other designations | |
Database references | |
SIMBAD | data |
Pi Centauri, Latinized from π Centauri, is a binary star system in the southern constellation of Centaurus. It has a blue-white hue and is visible to the naked eye with a combined apparent visual magnitude of +3.90.[2] The system is located at a distance of approximately 360 light years from the Sun based on parallax,[1] and is drifting further away with a radial velocity of around +9 km/s.[2] It is a member of the Lower Centaurus–Crux subgroup of the Scorpius–Centaurus association.[10]
The magnitude +4.08[3] primary, designated component A, is a B-type main-sequence star with a stellar classification of B5Vn,[4] where the 'n' suffix indicates broad, diffuse (nebulous) lines due to rapid rotation. This star is spinning with a projected rotational velocity of 340 km/s, giving it an equatorial bulge that is 22% larger than the polar radius.[8] It has 6.4[6] times the mass of the Sun and is radiating 783[2] times the Sun's luminosity from its photosphere at an effective temperature of 16,760 K.[7]
The secondary companion, component B, is magnitude +5.65[3] with a class of B6V[5] and 3.7[6] times the Sun's mass. The pair orbit around their common barycentre once every 39 years with an eccentricity of 0.8530. The semi-major axis of the companion is 0.23 arcseconds at an inclination of 19.4°.[6]