Omicron2 Centauri

From Wikipedia, the free encyclopedia
Jump to: navigation, search
ο2 Centauri
Centaurus constellation map.svg
link=ο2 Centauri

Location of ο2 Cen (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Centaurus
Right ascension 11h 31m 48.79948s[1]
Declination −59° 30′ 56.3276″[1]
Apparent magnitude (V) +5.14[2] (5.12 - 5.22[3])
Spectral type A2Iae
U−B color index −0.11[2]
B−V color index +0.49[2]
Variable type α Cyg[3]
Radial velocity (Rv) −16.8[4] km/s
Proper motion (μ) RA: -6.89 ± 0.26[1] mas/yr
Dec.: 1.12 ± 0.24[1] mas/yr
Parallax (π) 0.61 ± 0.28[1] mas
Distance approx. 5,000 ly
(approx. 1,600 pc)
Absolute magnitude (MV) −7.50[5]
Mass 18 M
Radius 131 R
Luminosity 105,000 L
Surface gravity (log g) 1.46 cgs
Temperature 9,080 K
Rotation 132 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

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

ο2 Centauri is a white A-type supergiant with a mean apparent magnitude of +5.12. It is approximately 5000 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.[5]

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


  1. ^ a b c d e van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752Freely accessible. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.  Vizier catalog entry
  2. ^ a b c Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D. 
  3. ^ a b Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S. 
  4. ^ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington. Bibcode:1953GCRV..C......0W. 
  5. ^ a b c Kaufer, A.; Stahl, O.; Wolf, B.; Gaeng, T.; Gummersbach, C. A.; Kovacs, J.; Mandel, H.; Szeifert, T. (1996). "Long-term spectroscopic monitoring of BA-type supergiants. I. Halpha_ line-profile variability.". Astronomy and Astrophysics. 305: 887–901. Bibcode:1996A&A...305..887K.