HD 93129A

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HD 93129A
ESO - The Carina Nebula (by).jpg
The Carina Nebula contains Eta Carinae and HD 93129A.
Observation data
Epoch J2000      Equinox J2000
Constellation Carina
Right ascension 10h 43m 57.5s
Declination −59° 32' 51.3"
Apparent magnitude (V) 6.97
Spectral type O2If*[1]
U−B color index −0.78
B−V color index 0.16
Mass 95[1] M
Radius 20[1] R
Luminosity 2,500,000[1] L
Temperature 52,000[1] K
Rotation 130[1]
Age 900,000 years
Database references

HD 93129A is one of the most luminous stars in the Milky Way.[2] This very young O class star is located about 7500 light-years from Earth in the bright nebula NGC 3372, the same nebula that harbors other super luminous stars, like Eta Carinae.

HD 93129A has a close neighbour within the same young cluster, an O3 supergiant (HD 93129B). In addition, HD93129A itself has recently been found to be a close binary, with the fainter companion being yet another very hot O3 star. The exact nature of the two components is not known accurately but they have been calculated to be 0.9 magnitudes apart in brightness and of similar (high) masses.[3] Luminosity data is still quoted here for the two stars combined but the actual luminosity of the primary will be only a little over half that value.


  1. ^ a b c d e f Cohen, D. H.; Gagné, M.; Leutenegger, M. A.; MacArthur, J. P.; Wollman, E. E.; Sundqvist, J. O.; Fullerton, A. W.; Owocki, S. P. (2011). "Chandra X-ray spectroscopy of the very early O supergiant HD 93129A: Constraints on wind shocks and the mass-loss rate". Monthly Notices of the Royal Astronomical Society 415 (4): 3354. arXiv:1104.4786. Bibcode:2011MNRAS.415.3354C. doi:10.1111/j.1365-2966.2011.18952.x.  edit
  2. ^ Kaler, James D. (2002). The Hundred Greatest Stars. Google Books: Copernicus Books. p. 50. ISBN 0-387-95436-8. Retrieved October 2014. 
  3. ^ Nelan, E. P.; Walborn, N. R.; Wallace, D. J.; Moffat, A. F. J.; Makidon, R. B.; Gies, D. R.; Panagia, N. (2004). "Resolving OB Systems in the Carina Nebula with theHubble Space TelescopeFine Guidance Sensor". The Astronomical Journal 128: 323. Bibcode:2004AJ....128..323N. doi:10.1086/420716.  edit

Further reading[edit]

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