Upsilon2 Centauri
Upsilon2 Centauri (υ2 Centauri) is a binary star system in the southern constellation Centaurus. It is visible to the naked eye with an apparent visual magnitude of +4.33. Based upon an annual parallax shift of just 2.57 mas as seen from Earth, this star is located roughly 1,300 light years from the Sun. Relative to its neighbors, the system has a peculiar velocity of 39.2+8.8
−15.2 km/s and it may form a runaway star system.
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 14h 01m 43.49909 s |
| Declination | −45° 36′ 12.2767″ |
| Apparent magnitude (V) | +4.33 |
| Characteristics | |
| Spectral type | F7 II/III |
| U−B color index | +0.26 |
| B−V color index | +0.61 |
| Variable type | None |
| Astrometry | |
| Radial velocity (Rv) | −7.8±7.4 km/s |
| Proper motion (μ) | RA: +8.64±1.09 mas/yr Dec.: −16.25±0.88 mas/yr |
| Parallax (π) | 2.57 ± 1.05 mas |
| Distance | approx. 1,300 ly (approx. 400 pc) |
| Absolute magnitude (MV) | −3.51 |
| Orbit | |
| Period (P) | 207.357 d |
| Eccentricity (e) | 0.55 |
| Periastron epoch (T) | 2423880.5 JD |
| Argument of periastron (ω) (secondary) | 88° |
| Semi-amplitude (K1) (primary) | 12.7 km/s |
| Details | |
| Mass | 6.86±0.39 M☉ |
| Luminosity (bolometric) | 3,919 L☉ |
| Surface gravity (log g) | 2.00 cgs |
| Temperature | 6,495 K |
| Rotational velocity (v sin i) | 0.0 km/s |
| Age | 45.9±4.0 Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is a single-lined spectroscopic binary star system with an orbital period of 207.357 days and an eccentricity of 0.55. The primary component has the spectrum of an evolved F-type giant/bright giant hybrid with a stellar classification of F7 II/III. It is around 46 million years old with 6.9 times the mass of the Sun. The star is radiating 3,919 times the Sun's luminosity from its photosphere at an effective temperature of 6,495 K.