HD 93129A

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HD 93129A
Image of the star cluster Trumpler 14 with HD 93129A being the brightest star in the image.
Observation data
Epoch J2000      Equinox J2000
Constellation Carina
Right ascension 10h 43m 57.5s[1]
Declination −59° 32' 51.3"[1]
Apparent magnitude (V) 7.310[1]
Spectral type O2If+O3.5V[2]
U−B color index −0.78[citation needed]
B−V color index 0.16[1]
Radial velocity (Rv) -14[3] km/s
Proper motion (μ) RA: -5.0[1] mas/yr
Dec.: 17.0[1] mas/yr
Distance 2,300[2] pc
Absolute magnitude (MV) -6.5[4]
Mass 95[2] M
Radius 20[2] R
Luminosity 2,500,000[2] L
Temperature 52,000[2] K
Rotational velocity (v sin i) 130[2] km/s
Age 900,000[citation needed] years
Database references

HD 93129A is a hot O class star in the Carina Nebula. It is one of the most luminous stars in the Milky Way.[2] It is the dominant member of the Trumpler 14 star cluster, a young star cluster within the Carina OB1 stellar association that harbors other super luminous stars, like Eta Carinae and WR 25.

HD 93129A has a close neighbour within Trumpler 14, an O3.5 main sequence star (HD 93129B) 3 arc-seconds away. In addition, HD93129A itself has recently been found to be a close binary, with the fainter companion being yet another very hot O3.5V. The components have been resolved, but their separation has decreased from 55 mas in 2004 and only 27 mas in 2013.[5] Luminosity data is still quoted here for the two stars combined. A further 5 fainter stars within 5 arc-seconds have been detected.[5]


  1. ^ a b c d e f Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics 355: L27. Bibcode:2000A&A...355L..27H. 
  2. ^ a b c d e f g h 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. 
  3. ^ Evans, D. S. (1967). "The Revision of the General Catalogue of Radial Velocities". Determination of Radial Velocities and their Applications 30: 57. Bibcode:1967IAUS...30...57E. 
  4. ^ Walborn, Nolan R.; Howarth, Ian D.; Lennon, Daniel J.; Massey, Philip; Oey, M. S.; Moffat, Anthony F. J.; Skalkowski, Gwen; Morrell, Nidia I.; Drissen, Laurent; Parker, Joel Wm. (2002). "A New Spectral Classification System for the Earliest O Stars: Definition of Type O2". The Astronomical Journal 123 (5): 2754. Bibcode:2002AJ....123.2754W. doi:10.1086/339831. 
  5. ^ a b Sana, H.; Le Bouquin, J.-B.; Lacour, S.; Berger, J.-P.; Duvert, G.; Gauchet, L.; Norris, B.; Olofsson, J.; Pickel, D.; Zins, G.; Absil, O.; De Koter, A.; Kratter, K.; Schnurr, O.; Zinnecker, H. (2014). "Southern Massive Stars at High Angular Resolution: Observational Campaign and Companion Detection". The Astrophysical Journal Supplement 215: 15. arXiv:1409.6304. Bibcode:2014ApJS..215...15S. doi:10.1088/0067-0049/215/1/15. 

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