R136c

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R136c
ESO - Eso1030a (by).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]
Orbit [4]
Period (P)17.2051 days
Eccentricity (e)0.31±0.08
Semi-amplitude (K1)
(primary)		51±9 km/s
Details [5]
Mass 142  M☉
Radius 40.7  R☉
Luminosity 3,800,000  L☉
Temperature 42,170  K
Rotational velocity (v sin i)<200 km/s
Age 1.8  Myr
Other designations
BAT99  112, RMC 136c, VFTS 1025 [5]
Database references
SIMBAD data

R136c is a likely binary star located in R136, a tight knot of stars at the centre of NGC 2070, an open cluster weighing 450,000 solar masses and containing 10,000 stars. [6] At 142  M☉ and 3.8 million L☉, it is the one of the most massive stars known and one of the most luminous, along with being one of the hottest, at over 40,000  K . It was first resolved and named by Feitzinger in 1980, along with R136a and R136b. [7]

Contents

Description

R136c is a Wolf–Rayet star of the spectral type WN5h and with a temperature of 42,170 K, making it one of hottest stars known. It is the one of the most massive stars known, with a mass of 142  M☉, and it is one of the most luminous stars known, with a luminosity of 3.8 million L☉. 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. [8]

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. [9] Absorption lines in the spectrum, tentatively assigned to the companion, indicate that it is considerably more massive than the Wolf-Rayet component. An orbit has been derived, but with low confidence and even the period is uncertain, between 5 and 47 days. [4]

Evolution

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. [8]

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. [10]

References

  1. 1 2 3 4 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: 1308.3412v1 . Bibcode:2013A&A...558A.134D. doi:10.1051/0004-6361/201321824. S2CID   118510909.
  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 (1): 624–659. arXiv: 1603.04994 . 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: 1303.2063 . Bibcode:2013Natur.495...76P. doi:10.1038/nature11878. PMID   23467166. S2CID   4417699.
  4. 1 2 Shenar, T.; Sana, H.; Crowther, P. A.; Bostroem, K. A.; Mahy, L.; Najarro, F.; Oskinova, L.; Sander, A. A. C. (2023). "Constraints on the multiplicity of the most massive stars known: R136 a1, a2, a3, and C". Astronomy and Astrophysics. 679: A36. arXiv: 2309.13113 . Bibcode:2023A&A...679A..36S. doi:10.1051/0004-6361/202346930.
  5. 1 2 Schneider, F. R. N.; Sana, H.; Evans, C. J.; Bestenlehner, J. M.; Castro, N.; Fossati, L.; Gräfener, G.; Langer, N.; Ramírez-Agudelo, O. H.; Sabín-Sanjulián, C.; Simón-Díaz, S.; Tramper, F.; Crowther, P. A.; de Koter, A.; de Mink, S. E.; Dufton, P. L.; Garcia, M.; Gieles, M.; Hénault-Brunet, V.; Herrero, A.; Izzard, R. G.; Kalari, V.; Lennon, D. J.; Maíz Apellániz, J.; Markova, N.; Najarro, F.; Podsiadlowski, Ph.; Puls, J.; Taylor, W. D.; van Loon, J. Th.; Vink, J. S.; Norman, C. (2018). "An excess of massive stars in the local 30 Doradus starburst". Science. 359 (6371): 69–71. arXiv: 1801.03107 . Bibcode:2018Sci...359...69S. doi:10.1126/science.aan0106. PMID   29302009. S2CID   206658504.
  6. ↑ Bosch, Guillermo; Terlevich, Elena; Terlevich, Roberto (2009). "Gemini/GMOS Search for Massive Binaries in the Ionizing Cluster of 30 Dor". Astronomical Journal. 137 (2): 3437–3441. arXiv: 0811.4748 . Bibcode:2009AJ....137.3437B. doi:10.1088/0004-6256/137/2/3437. S2CID   17976455.
  7. ↑ 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 (1–2): 50. Bibcode:1980A&A....84...50F.
  8. 1 2 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 . S2CID   53001712.
  9. ↑ 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. S2CID   55123954.
  10. ↑ 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. S2CID   84177572.
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