Omicron2 Centauri
Variable star in the constellation Centaurus
title: "Omicron2 Centauri" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["a-type-supergiants", "alpha-cygni-variables", "centaurus", "bayer-objects", "bright-star-catalogue-objects", "durchmusterung-objects", "henry-draper-catalogue-objects", "hipparcos-objects"] description: "Variable star in the constellation Centaurus" topic_path: "general/a-type-supergiants" source: "https://en.wikipedia.org/wiki/Omicron2_Centauri" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Variable star in the constellation Centaurus ::
| name = ο2 Centauri | image = |image=Centaurus constellation map.svg |float=center |alt= |label= |position=right |width=280 |mark=Red circle.svg |mark_width=10 |mark_link=ο2 Centauri |x=840|y=894 | caption = Location of ο2 Cen (circled) | epoch = J2000.0 | constell = Centaurus | ra = | dec = | appmag_v = +5.14 (5.12 - 5.22) | class = A2Iae | b-v = +0.49 | u-b = −0.11 | variable = α Cyg | type = Blue supergiant | radial_v = −16.8 | prop_mo_ra = −6.976 | prop_mo_dec = +1.118 | pm_footnote = | parallax = 0.4665 | p_error = 0.0713 | parallax_footnote = | absmag_v = −7.50 | source= | mass = 18 | radius = 131 | luminosity = 105,000 | temperature = 9,080 | metal_fe = | gravity = 1.46 | rotation = 132 days | rotational_velocity = 50 | age_gyr = | names = | Simbad = HD+100262
Omicron2 Centauri is a star in the southern constellation Centaurus. Its name is a Bayer designation that is Latinied from ο2 Centauri, and abbreviated Omicron2 Cen or ο2 Cen. This star is visible to the naked eye with a mean apparent visual magnitude of +5.12. Based on parallax measurements, it is located at a distance of approximately 7,000 light years from Earth.
ο2 Centauri is a white A-type blue supergiant. 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 (possibly a yellow hypergiant). Both stars are located between Crux (the Southern Cross) and the brightest yellow hypergiant in the sky, V382 Carinae.
References
| access-date=2025-12-24 }}
| title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system | last=Ducati | first=J. R. | journal=CDS/ADC Collection of Electronic Catalogues | volume=2237 | year=2002 | bibcode=2002yCat.2237....0D }}
| title=VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013) | journal=VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S | last1=Samus | first1=N. N. | last2=Durlevich | first2=O. V. | display-authors=etal | volume=1 | year=2009 | bibcode=2009yCat....102025S }}
| title=General catalogue of stellar radial velocities | last=Wilson | first=Ralph Elmer | year=1953 | publisher=Carnegie Institution of Washington | bibcode=1953GCRV..C......0W }}
| title=Long-term spectroscopic monitoring of BA-type supergiants. I. Halpha_ line-profile variability | last1=Kaufer | first1=A. | last2=Stahl | first2=O. | last3=Wolf | first3=B. | last4=Gaeng | first4=T. | last5=Gummersbach | first5=C. A. | last6=Kovacs | first6=J. | last7=Mandel | first7=H. | last8=Szeifert | first8=T. | display-authors=1 | journal=Astronomy and Astrophysics | volume=305 | pages=887–901 | year=1996 | bibcode=1996A&A...305..887K }}
References
- {{cite Gaia DR3. 5336114548828274560
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