Melnick 34

BAT99-116
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Dorado
Right ascension 5h 38m 44.26s[1]
Declination −69° 06′ 05.88″[1]
Apparent magnitude (V) 13.09[1]
Characteristics
Evolutionary stage Wolf–Rayet star
Spectral type WN5h:a[2]
B−V color index +0.25[1]
Astrometry
Distance163,000 ly
(49,970[3] pc)
Absolute magnitude (MV)-7.9[1]
Details
Mass179[4] M☉
Radius20[2] R☉
Luminosity7,079,000[5] L☉
Temperature53,000[1] K
Age~1.7[6] Myr
Other designations
BAT99 116, [HSH95] 8, Melnick 34, 2MASS J05384424-6906058, Brey 84
Database references
SIMBADdata

BAT99-116 (commonly called Melnick 34 or Mk34) is a massive luminous Wolf–Rayet star near R136 in the 30 Doradus complex (also known as the Tarantula Nebula) in the Large Magellanic Cloud.

Binary

NGC 2070 region. MK 34 is the bright isolated star to the left of the R136 cluster in the righthand panel.

Melnick 34 is thought to be a binary star with an orbital period of 155 days. It shows high x-ray luminosity characteristic of colliding-wind binaries, and periodic variations in luminosity, spectral absorption, and the x-ray brightness.[7]

Physical characteristics

R136 in NGC 2070, with Mk 34 just to the left of the central concentration

Mk34 is a Wolf–Rayet star with surface temperature over 50,000 K .[2][1] It is estimated that at its birth the star was around 275 M☉.[5] It has a powerful stellar wind and despite its young age it has already shed a large fraction of its initial mass.[4] Because the Mk 34 system includes two massive luminous stars that cannot be resolved, estimates of the temperature, luminosity, and mass of each are highly uncertain.[2]

Evolution

Mk34 is currently burning hydrogen in its core, although it shows strong helium and nitrogen emission due to convection of fusion products from the core to the surface. It is expected that it will evolve quickly to a hydrogen-free Wolf-Rayet star, possibly with a short time as a blue hypergiant and luminous blue variable. It will then shed more and more of its outer layers, ultimately becoming a WO star close to 200,000 K before collapsing, producing a type Ic supernova and leaving behind a black hole.[8]

References

  1. 1 2 3 4 5 6 7 Doran, E. I.; Crowther, P. A.; de Koter, A.; Evans, C. J.; McEvoy, C.; Walborn, N. R.; Bastian, N.; Bestenlehner, J. M.; Grafener, G.; Herrero, A.; Kohler, K.; Maiz Apellaniz, J.; Najarro, F.; Puls, J.; Sana, H.; Schneider, F. R. N.; Taylor, W. D.; van Loon, J. Th.; Vink, J. S. (2013). "The VLT-FLAMES Tarantula Survey - XI. A census of the hot luminous stars and their feedback in 30 Doradus". Astronomy & Astrophysics. 558: 134. arXiv:1308.3412. Bibcode:2013A&A...558A.134D. doi:10.1051/0004-6361/201321824.
  2. 1 2 3 4 Hainich, R.; Rühling, U.; Todt, H.; Oskinova, L. M.; Liermann, A.; Gräfener, G.; Foellmi, C.; Schnurr, O.; Hamann, W. -R. (2014). "The Wolf-Rayet stars in the Large Magellanic Cloud". Astronomy & Astrophysics. 565: A27. arXiv:1401.5474. Bibcode:2014A&A...565A..27H. doi:10.1051/0004-6361/201322696.
  3. ↑ Pietrzyński, G; D. Graczyk; W. Gieren; I. B. Thompson; B. Pilecki; A. Udalski; I. Soszyński; et al. (7 March 2013). "An eclipsing-binary distance to the Large Magellanic Cloud accurate to two per cent". Nature. 495 (7439): 76–79. arXiv:1303.2063. Bibcode:2013Natur.495...76P. doi:10.1038/nature11878. PMID 23467166.
  4. 1 2 Portegies Zwart, Simon F.; Pooley, David; Lewin, Walter H. G. (2002). "A Dozen Colliding-Wind X-Ray Binaries in the Star Cluster R136 in the 30 Doradus Region". The Astrophysical Journal. 574 (2): 762. arXiv:astro-ph/0106109. Bibcode:2002ApJ...574..762P. doi:10.1086/340996.
  5. 1 2 Crowther, Paul A.; Caballero-Nieves, S. M.; Bostroem, K. A.; Maíz Apellániz, J.; Schneider, F. R. N.; Walborn, N. R.; Angus, C. R.; Brott, I.; Bonanos, A.; De Koter, A.; De Mink, S. E.; Evans, C. J.; Gräfener, G.; Herrero, A.; Howarth, I. D.; Langer, N.; Lennon, D. J.; Puls, J.; Sana, H.; Vink, J. S. (2016). "The R136 star cluster dissected with Hubble Space Telescope/STIS. I. Far-ultraviolet spectroscopic census and the origin of He II λ1640 in young star clusters". Monthly Notices of the Royal Astronomical Society. 458: 624. arXiv:1603.04994. Bibcode:2016MNRAS.458..624C. doi:10.1093/mnras/stw273.
  6. ↑ Crowther, P. A.; Schnurr, O.; Hirschi, R.; Yusof, N.; Parker, R. J.; Goodwin, S. P.; Kassim, H. A. (2010). "The R136 star cluster hosts several stars whose individual masses greatly exceed the accepted 150 M⊙ stellar mass limit". Monthly Notices of the Royal Astronomical Society. 408 (2): 731. arXiv:1007.3284. Bibcode:2010MNRAS.408..731C. doi:10.1111/j.1365-2966.2010.17167.x.
  7. ↑ Pollock, A. M. T; Crowther, P. A; Tehrani, K; Broos, Patrick S; Townsley, Leisa K (2017). "The 155-day X-ray cycle of the very massive Wolf-Rayet star Melnick 34 in the Large Magellanic Cloud". Monthly Notices of the Royal Astronomical Society. arXiv:1803.00822. Bibcode:2018MNRAS.474.3228P. doi:10.1093/mnras/stx2879.
  8. ↑ Groh, J. H.; Meynet, G.; Georgy, C.; Ekström, S. (2013). "Fundamental properties of core-collapse supernova and GRB progenitors: Predicting the look of massive stars before death". Astronomy & Astrophysics. 558: A131. arXiv:1308.4681. Bibcode:2013A&A...558A.131G. doi:10.1051/0004-6361/201321906.

Coordinates: 05h 38m 44.25s, −69° 06′ 05.8″

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