Global InformationChi2 Orionis information
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Orion |
| Right ascension | 06h 03m 55.18437s[1] |
| Declination | +20° 08′ 18.4281″[1] |
| Apparent magnitude (V) | 4.63[2][3] |
| Characteristics | |
| Spectral type | B2Ia[2] |
| U−B color index | −0.68[3] |
| B−V color index | +0.28[3] |
| R−I color index | +0.22[3] |
| Variable type | α Cyg[4] |
| Astrometry | |
| Radial velocity (Rv) | 16.8±0.9[5] km/s |
| Proper motion (μ) | RA: 2.679[1] mas/yr Dec.: −2.500[1] mas/yr |
| Parallax (π) | 0.7636 ± 0.1219 mas[1] |
| Distance | approx. 4,300 ly (approx. 1,300 pc) |
| Absolute magnitude (MV) | −7.6[2] |
| Details | |
| Mass | 42.3±1.0[6] M☉ |
| Radius | 61.9[2] R☉ |
| Luminosity | 446,000[2] L☉ |
| Surface gravity (log g) | 2.35[2] cgs |
| Temperature | 19,000[2] K |
| Rotational velocity (v sin i) | 72[2] km/s |
| Age | 5±0.6[6] Myr |
| Other designations | |
χ2 Ori, Chi2 Orionis, Chi2 Ori, 62 Orionis, 62 Ori, BD+20 1233, GC 7675, HD 41117, HIP 28716, HR 2135, PPM 95316, SAO 77911 | |
| Database references | |
| SIMBAD | data |
Chi2 Orionis (Chi2 Ori / χ2 Orionis / χ2 Ori) /kaɪ.tuːˈɒraɪ/ is a B-type supergiant star in the constellation of Orion. It has an apparent visual magnitude of 4.63 but being quite distant, and heavily extinguished it burns with the greatest absolute visual light magnitude among stars in Orion within the near reaches of the galaxy, 0.9 of a magnitude brighter than Rigel.[citation needed] Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified. It is considered to be a member of the Gemini OB1 association.[2]
In apparent brightness it ranks, within Orion, admitting the higher published mean brightness of much more variable stars ranked above it, 35th.[citation needed]
Chi1 Orionis is an unrelated, yellow, main sequence star over two degrees away.
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