Omicron2 Centauri

Omicron2 Centauri (ο2 Cen, ο2 Centauri) is a star in the constellation Centaurus.

ο2 Centauri
Location of ο2 Cen (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Centaurus
Right ascension 11h 31m 48.79955s
Declination −59° 30 56.3296
Apparent magnitude (V) +5.14 (5.12 - 5.22)
Characteristics
Spectral type A2Iae
U−B color index −0.11
B−V color index +0.49
Variable type α Cyg
Astrometry
Radial velocity (Rv)−16.8 km/s
Proper motion (μ) RA: −6.976 mas/yr
Dec.: +1.118 mas/yr
Parallax (π)0.4665 ± 0.0713 mas
Distanceapprox. 7,000 ly
(approx. 2,100 pc)
Absolute magnitude (MV)−7.50
Details
Mass18 M
Radius131 R
Luminosity105,000 L
Surface gravity (log g)1.46 cgs
Temperature9,080 K
Rotation132 days
Rotational velocity (v sin i)50 km/s
Other designations
HR 4442, HD 100262, CD−58°4101, FK5 2920, HIP 56250, SAO 239146, GC 15820
Database references
SIMBADdata

ο2 Centauri is a white A-type supergiant with a mean apparent magnitude of +5.12. It is approximately 7,000 light years from Earth. It is classified as an Alpha Cygni type variable star and its brightness varies from magnitude +5.12 to +5.22 with a period of 46.3 days.

In 1996, Kaufer and colleagues calculated Omicron2 Centauri to be around 136,000 times as luminous, 18 times as massive and have 131 times the diameter of the Sun.

ο2 Cen forms a close naked eye pair with ο1 Cen, another 5th magnitude supergiant.

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