R136

R136 (formally known as RMC 136 from the Radcliffe Observatory Magellanic Clouds catalogue[4]) is the central concentration of stars in the NGC 2070 star cluster, which lies at the centre of the Tarantula Nebula in the Large Magellanic Cloud. When originally named it was an unresolved stellar object (catalogued as HD 38268 and Wolf-Rayet star Brey 82) but is now known to include 72 class O and Wolf–Rayet stars within 5 parsecs (20 arc seconds) of the centre of the cluster.[5] The extreme number and concentration of young massive stars in this part of the LMC qualifies it as a starburst region.[6]

R136
In ultraviolet, visible, and red light by Hubble Space Telescope Wide Field Camera 3
Credit: NASA, ESA
Observation data (J2000.0 epoch)
ConstellationDorado
Right ascension 05h 38m 42.396s[1]
Declination−69° 06′ 03.36″[1]
Distance157 kly (48.5 kpc)
Apparent magnitude (V)9.50
Physical characteristics
Mass90,000[2] M☉
Estimated age1.5+0.3
−0.7 million years[2]
Other designationsUCAC2 1803442, SAO 249329, HD 38268, TYC 9163-1014-1, CD-69 324, GC 7114[3]

Properties

R136 produces most of the energy that makes the Tarantula Nebula visible. The estimated mass of the cluster is 450,000 solar masses, suggesting it may become a globular cluster in the future.[7] R136 has around 200 times the stellar density of a typical OB association such as Cygnus OB2.[8] The central R136 concentration of the cluster is about 2 parsecs across, although the whole NGC 2070 cluster is much larger.[8]

R136 is thought to be less than 2 million years old.[8][9] None of the member stars is significantly evolved and none is thought to have exploded as supernova. The brightest stars are WNh, O supergiants, and OIf/WN slash stars, all extremely massive fully convective stars. There are no red supergiants, blue hypergiants, or luminous blue variables within the cluster. A small number of class B stars have been detected in the outskirts of the cluster, but less massive and less luminous stars cannot be resolved from the dense cluster core at the large distance of the LMC.[5]

R136a

R136a is the bright knot at the centre of R136.[2]

Components

The cluster R136 contains many of the most massive and luminous stars known, including R136a1. Within the central 5 parsecs there are 32 of the hottest type O stars (O2.0–3.5), 40 other O stars, and 12 Wolf-Rayet stars, mostly of the extremely luminous WNh type. Within 150 parsecs there are a further 325 O stars and 19 Wolf-Rayet stars.[5] Several runaway stars have been associated with R136, including VFTS 682.[10]

R136 was first resolved into three components R136a, R136b, and R136c. R136a was resolved using speckle interferometry and eventually space-based observations into as many as 24 components,[11] dominated by R136a1, R136a2, and R136a3, all three being extremely massive WNh stars several million times more luminous than the sun.

NameRight ascension[5]Declination[5]V[2] (F555W)Spectral type[2]MV[2] (F555W)Temperature (K)[2]Luminosity (L☉)[2]Mass (M☉)[2]
Basic data for the original RMC 136 a/b/c stars
R136a1 05h 38m 42.39s−69° 06′ 02.91″12.28WN5h−8.0953,0008,710,000315
R136a2 05h 38m 42.40s−69° 06′ 02.88″12.80WN5h−7.5253,0004,266,000195
R136a3 05h 38m 42.33s−69° 06′ 03.27″12.97WN5h−7.3953,0003,802,000180
R136a4 05h 38m 42.34s−69° 06′ 02.60″13.96O2–3V−6.5151,0002,884,000124
R136a5 05h 38m 42.43s−69° 06′ 02.73″13.71O2If*−6.6550,0002,089,000101
R136a6 05h 38m 42.29s−69° 06′ 03.37″13.35O2If−6.9646,0003,311,000150
R136a7 05h 38m 42.41s−69° 06′ 02.57″13.97O3III(f*)−6.1046,000977,00069
R136a8 05h 38m 42.37s−69° 06′ 01.9″?14.42O2–3V−6.0551,0001,905,00096
R136b 05h 38m 42.74s−69° 06′ 03.78″13.24O4If/WN8−7.3141,0001,995,00093
R136c 05h 38m 42.90s−69° 06′ 04.83″12.86WN5h−7.9[5]51,0005,623,000230
  • R136 observed with Hubble's WFC3.[12]
  • Runaway star speeding from 30 Doradus, image taken by the Hubble Space Telescope.
  • R136 in infrared (Hubble Space Telescope)
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See also
  • Hodge 301, an older massive star cluster in Tarantula Nebula.
  • NGC 2060, a smaller open cluster near R136.

References
  1. 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. pp. L27. Bibcode:2000A&A...355L..27H. doi:10.1888/0333750888/2862. ISBN 978-0333750889.
  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. "RMC 136". SIMBAD. Centre de données astronomiques de Strasbourg.
  4. Feast, M. W.; Thackeray, A. D.; Wesselink, A. J. (1960). "The brightest stars in the Magellanic Clouds". Monthly Notices of the Royal Astronomical Society. 121 (4): 337. Bibcode:1960MNRAS.121..337F. doi:10.1093/mnras/121.4.337.
  5. 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:1308.3412. Bibcode:2013A&A...558A.134D. doi:10.1051/0004-6361/201321824.
  6. Brandl, B.; Sams, B. J.; Bertoldi, F.; Eckart, A.; Genzel, R.; Drapatz, S.; Hofmann, R.; Loewe, M.; Quirrenbach, A. (1996). "Adaptive Optics Near-Infrared Imaging of R136 in 30 Doradus: The Stellar Population of a Nearby Starburst". The Astrophysical Journal. 466: 254. Bibcode:1996ApJ...466..254B. doi:10.1086/177507.
  7. 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.
  8. Massey, P.; Hunter, D. A. (1998). "Star Formation in R136: A Cluster of O3 Stars Revealed by Hubble Space Telescope Spectroscopy". The Astrophysical Journal. 493 (1): 180. Bibcode:1998ApJ...493..180M. doi:10.1086/305126.
  9. 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.
  10. Banerjee, S.; Kroupa, P.; Oh, S. (2012). "Runaway Massive Stars from R136: Vfts 682 is Very Likely A "Slow Runaway"". The Astrophysical Journal. 746 (1): 15. arXiv:1111.0291. Bibcode:2012ApJ...746...15B. doi:10.1088/0004-637X/746/1/15.
  11. Campbell, B.; Hunter, D. A.; Holtzman, J. A.; Lauer, T. R.; Shayer, E. J.; Code, A.; Faber, S. M.; Groth, E. J.; Light, R. M.; Lynds, R.; O'Neil, E. J. , J.; Westphal, J. A. (1992). "Hubble Space Telescope Planetary Camera images of R136" (PDF). The Astronomical Journal. 104: 1721. Bibcode:1992AJ....104.1721C. doi:10.1086/116355.
  12. "R136 observed with WFC3". Retrieved 23 March 2016.

Further reading
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