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[3]
B−V color index +0.22[3]
Radial velocity (Rv) −0.4 ± 7.4[4] 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[5] (−6.1 + −5.2[6])
Mass 110[6] M
Radius 22.5[7] R
Luminosity 1,500,000[7] L
Surface gravity (log g) 3.71[7] cgs
Temperature 42,500[7] K
Rotational velocity (v sin i) 130[7] km/s
Mass 70[6] M
Age 0.9+0.2
[4] Myr
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, HD 93129A itself has recently been found to be a close binary,[8] 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.[9] Luminosity data is still quoted here for the two stars combined. A further 5 fainter stars within 5 arc-seconds have been detected.[9]


  1. ^ a b c d e 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 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): 3354–3364. arXiv:1104.4786free to read. Bibcode:2011MNRAS.415.3354C. doi:10.1111/j.1365-2966.2011.18952.x. 
  3. ^ a b Simon, K. P.; Kudritzki, R. P.; Jonas, G.; Rahe, J. (1983). "Non-LTE analysis of massive O stars. III - the O3 stars HD 93128, HD 93129A, and HDE 303308". Astronomy and Astrophysics. 125: 34. Bibcode:1983A&A...125...34S. 
  4. ^ a b Penny, Laura R.; Gies, Douglas R.; Hartkopf, William I.; Mason, Brian D.; Turner, Nils H. (1993). "The frequency of binary stars in the young cluster Trumpler 14". Publications of the Astronomical Society of the Pacific. 105: 588. Bibcode:1993PASP..105..588P. doi:10.1086/133200. 
  5. ^ 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): 2754–2771. Bibcode:2002AJ....123.2754W. doi:10.1086/339831. 
  6. ^ a b c Nelan, Edmund P.; Walborn, Nolan R.; Wallace, Debra J.; Moffat, Anthony F. J.; Makidon, Russell B.; Gies, Douglas R.; Panagia, Nino (2004). "Resolving OB Systems in the Carina Nebula with the Hubble Space Telescope Fine Guidance Sensor". The Astronomical Journal. 128: 323–329. Bibcode:2004AJ....128..323N. doi:10.1086/420716. 
  7. ^ a b c d e Repolust, T.; Puls, J.; Herrero, A. (2004). "Stellar and wind parameters of Galactic O-stars. The influence of line-blocking/blanketing". Astronomy and Astrophysics. 415: 349–376. Bibcode:2004A&A...415..349R. doi:10.1051/0004-6361:20034594. 
  8. ^ Benaglia, P.; Koribalski, B. (2004). "Radio observations of HD 93129A: The earliest O star with the highest mass loss?". Astronomy & Astrophysics. 416 (1): 171–178. arXiv:astro-ph/0312003free to read. Bibcode:2004A&A...416..171B. doi:10.1051/0004-6361:20034138. 
  9. ^ 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:1409.6304free to read. Bibcode:2014ApJS..215...15S. doi:10.1088/0067-0049/215/1/15. 

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