32 Orionis
Triple star system in the constellation Orion
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32 Orionis is a triple[3] star system in the equatorial constellation of Orion. It has the Bayer designation A Orionis, while 32 Orionis is the Flamsteed designation. This system is visible to the naked eye as a faint point of light with a combined apparent visual magnitude of 4.20.[2] It is located approximately 303 light-years away from the Sun based on parallax,[1] and is drifting further away with a radial velocity of +18.6 km/s.[4]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Orion |
| Right ascension | 05h 30m 47.05091s[1] |
| Declination | +05° 56′ 53.2925″[1] |
| Apparent magnitude (V) | 4.20[2] (4.43 + 5.80)[3] |
| Characteristics | |
| Spectral type | B5V + ? + B7V[3] |
| U−B color index | –0.56[2] |
| B−V color index | –0.13[2] |
| Astrometry | |
| Radial velocity (Rv) | +18.60[4] km/s |
| Proper motion (μ) | RA: +5.10[1] mas/yr Dec.: –33.30[1] mas/yr |
| Parallax (π) | 10.77±0.64 mas[1] |
| Distance | 300 ± 20 ly (93 ± 6 pc) |
| Absolute magnitude (MV) | –0.63[5] |
| Details | |
| 32 Ori A | |
| Mass | 5.0[6] M☉ |
| Radius | 2.9[7] R☉ |
| Luminosity | 388[5] L☉ |
| Surface gravity (log g) | 4.40[8] cgs |
| Temperature | 16,020[9] K |
| Rotational velocity (v sin i) | 169[8] km/s |
| Age | 65[8] Myr |
| Other designations | |
| A Ori, 32 Ori, NSV 14617, BD+05°939, GC 6813, HD 36267, HIP 25813, HR 1839, SAO 112849, CCDM J05308+0557AB, WDS J05308+0557AB[10] | |
| Database references | |
| SIMBAD | data |
The system is a member of the eponymous 32 Orionis group, a young, nearby association of 46 co-moving stars first discovered in 2007.[11] Research in 2015 suggested that Bellatrix is a probable member of the group due to its distance and position in the sky and suggested it be called the Bellatrix Cluster,[12] although further research in 2017 called Bellatrix's membership into question due to its proper motion deviating significantly from the group.[11]
The primary component of this system is a B-type main-sequence star with a stellar classification of B5V[13] and a magnitude around 4.43. This is actually a spectroscopic binary with an orbital period of 3.964 days and eccentricity of 0.38.[3] The unseen companion has an estimated mass of 0.6 times that of the Sun.[14] Component B, at an angular separation of 1.08″ from the primary, is a class B7V star with a magnitude of 5.8, orbiting with the primary at a period of 614 years and eccentricity 0.22.[15]