R136c

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R136c
RMC136 cluster.jpg
The bright star to the left of the cluster core is R136c.
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Dorado
Right ascension 5h 38m 42.90s[1]
Declination −69° 06′ 04.83″[1]
Apparent magnitude (V) 12.86[1]
Characteristics
Evolutionary stage Wolf-Rayet star
Spectral type WN5h[2]
Astrometry
Distance 163,000 ly
(49,970[3] pc)
Absolute magnitude (MV) −7.9[1]
Details[2]
Mass 230 M
Radius 18.4[4] R
Luminosity 5,623,000 L
Temperature 51,000 K
Age ~1.7[5] Myr
Other designations
BAT99 112, RMC 136c
Database references
SIMBAD data

R136c is located in the R136 super star cluster, a massive star cluster with 450,000 solar masses and 10,000 stars. It was first resolved and named by Feitzinger in 1980, along with R136a and R136b.[6]

Description[edit]

R136c is a Wolf-Rayet star of the spectral type WN5h and with a temperature of 51,000 K. It is 230 times the mass of the sun and over five million times more luminous. The extreme luminosity is produced by the CNO fusion process in its highly compressed hot core. Typical of all Wolf-Rayet stars, R136c has been losing mass by means of a strong stellar wind with speeds over 2,000 km/s and mass loss rates in excess of 10−5 solar masses per year.[5] It is strongly suspected to be a binary, due to the detection of hard x-ray emission typical of colliding wind binaries, but the companion is thought to make only a small contribution to the total luminosity.[4]

Death[edit]

R136c is so energetic that it has already lost a substantial fraction of its initial mass, even though it is only a few million years old. It is still effectively on the main sequence, fusing hydrogen at its core via the CNO cycle, but it has convected and mixed fusion products to the surface and these create a powerful stellar wind and emission spectrum normally only seen in highly evolved stars.[5]

Its fate depends on the amount of mass it loses before its core collapses, but is likely to result in a supernova. The most recent models for single star evolution at near-solar metallicities suggest that the most massive stars explode as highly stripped type Ic supernovae, although different outcomes are possible for binaries. Some of these supernovae are expected to produce a type of gamma-ray burst and the expected remnant is a black hole.[7]

References[edit]

  1. ^ a b c d 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: A134. arXiv:1308.3412v1free to read. Bibcode:2013A&A...558A.134D. doi:10.1051/0004-6361/201321824. 
  2. ^ a b 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:1603.04994free to read. Bibcode:2016MNRAS.458..624C. doi:10.1093/mnras/stw273. 
  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:1303.2063free to read. Bibcode:2013Natur.495...76P. doi:10.1038/nature11878. PMID 23467166. 
  4. ^ a b 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:1401.5474free to read. Bibcode:2014A&A...565A..27H. doi:10.1051/0004-6361/201322696. 
  5. ^ a b c 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:1007.3284free to read. Bibcode:2010MNRAS.408..731C. doi:10.1111/j.1365-2966.2010.17167.x. 
  6. ^ Feitzinger, J. V.; Schlosser, W.; Schmidt-Kaler, T.; Winkler, C. (1980). "The central object R 136 in the gas nebula 30 Doradus - Structure, color, mass and excitation parameter". Astronomy and Astrophysics. 84: 50. Bibcode:1980A&A....84...50F. 
  7. ^ 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:1308.4681free to read. Bibcode:2013A&A...558A.131G. doi:10.1051/0004-6361/201321906.