Bellatrix
Bellatrix is the third-brightest star in the constellation of Orion, positioned 5° west of the red supergiant Betelgeuse (Alpha Orionis). It has the Bayer designation γ Orionis, which is Latinized to Gamma Orionis. With a slightly variable magnitude of around 1.6, it is typically the 25th-brightest star in the night sky. Located at a distance of 250±10 light-years from the Sun, it is a blue giant star around 7.7 times as massive as the sun with 5.75 times its diameter.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Orion |
| Pronunciation | /ˈbɛlətrɪks/ /bɛˈleɪtrɪks/ |
| Right ascension | 05h 25m 07.86325s |
| Declination | +06° 20′ 58.9318″ |
| Apparent magnitude (V) | 1.64 (1.59 - 1.64) |
| Characteristics | |
| Spectral type | B2 III or B2V |
| U−B color index | −0.86 |
| B−V color index | −0.21 |
| Variable type | Suspected |
| Astrometry | |
| Radial velocity (Rv) | +18.2 km/s |
| Proper motion (μ) | RA: −8.11 mas/yr Dec.: −12.88 mas/yr |
| Parallax (π) | 12.92 ± 0.52 mas |
| Distance | 250 ± 10 ly (77 ± 3 pc) |
| Absolute magnitude (MV) | −2.78 |
| Details | |
| Mass | 7.7 M☉ |
| Radius | 5.75 R☉ |
| Luminosity | 9,211 L☉ |
| Surface gravity (log g) | 3.60 cgs |
| Temperature | 21,800 K |
| Metallicity [Fe/H] | −0.07 dex |
| Rotational velocity (v sin i) | 52 km/s |
| Age | 25.2 Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
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