Chi2 Orionis

For other stars with this Bayer designation, see χ Orionis.
χ2 Orionis
Location of χ2 Orionis (circled)
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
Evolutionary stage Blue supergiant
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]
Distanceapprox. 4,300 ly
(approx. 1,300 pc)
Absolute magnitude (MV)−7.6[2]
Details
Mass42.3±1.0[6] M☉
Radius61.9[2] R☉
Luminosity446,000[2] L☉
Surface gravity (log g)2.35[2] cgs
Temperature19,000[2] K
Rotational velocity (v sin i)72[2] km/s
Age5±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
SIMBADdata

Chi2 Orionis (Chi2 Ori / χ2 Orionis / χ2 Ori) /kaɪ.tuːˈɒraɪ/ is a B-type blue 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 and far closer to the Sun.

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  3. ^ a b c d Cite error: The named reference bsc1 was invoked but never defined (see the help page).
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  5. ^ Cite error: The named reference rv was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Neuhauser was invoked but never defined (see the help page).