R136

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R136


Credit: In ultraviolet, visible, and red light by Hubble Space Telescope Wide Field Camera 3
Observation data (J2000.0 epoch)
Constellation Dorado
Right ascension 05h 38m 42.396s
Declination −69° 06′ 03.36″
Distance 157 kly (48.5 kpc)
Apparent magnitude (V) 9.50
Physical characteristics
Other designations UCAC2 1803442, SAO 249329, HD 38268, TYC 9163-1014-1, CD-69 324, GC 7114[1]

R136 (formally known as RMC 136 from the Radcliffe Observatory Magellanic Clouds catalogue[2]) 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.[3] The extreme number and concentration of young massive stars in this part of the LMC qualifies it as a starburst region.[4]

Properties

R136 in infrared (Hubble Space Telescope)

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.[5] R136 has around 200 times the stellar density of a typical OB association such as Cygnus OB2.[6] The central R136 concentration of the cluster is about 2 parsecs across, although the whole NGC 2070 cluster is much larger.[6]

R136 is thought to be less than 2 million years old.[6][7] None of the member stars are significantly evolved and none are thought to have exploded as supernovae. 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.[3]

R136a

R136a is the bright knot at the centre of R136.

Components

Runaway star speeding from 30 Doradus, image taken by The Hubble Space Telescope

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 - O3.5), 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.[3] Several runaway stars have been associated with R136, including VFTS 682.[8]

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,[9] dominated by R136a1, R136a2, and R136a3, all three being extremely massive WNh stars several million times more luminous than the sun.

Name Right ascension Declination V Spectral type MV Temperature (K) Luminosity (L☉)
R136a1 05h 38m 42.39s −69° 06′ 02.9″ 12.23 WN5h -7.6 56,000 8,700,000
R136a2 05h 38m 42.40s −69° 06′ 02.9″ 12.34 WN5h -7.8 53,000 4,900,000
R136a3 05h 38m 42.33s −69° 06′ 03.3″ 12.97 WN5h -7.4 53,000 3,200,000
R136a4[10] 05h 38m 42.34s −69° 06′ 02.6″ 13.41 (O3V) -5.7 ~50,000 980,000
R136a5[3] 05h 38m 42.43s −69° 06′ 02.7″ 13.71 O2If* -6.3 46,000 1,250,000
R136a6[10] 05h 38m 42.29s −69° 06′ 03.4″ 13.35 (O3V) -5.8 ~50,000 1,000,000
R136a7[3] 05h 38m 42.48s −69° 06′ 02.6″ 13.97 O3III(f*) -5.7 47,000 630,000
R136a8[10] 05h 38m 42.37s −69° 06′ 01.9″ 14.2 (O3V) -5.5 ~50,000 760,000
R136b 05h 38m 42.74s −69° 06′ 03.8″ 13.24 WN9ha -7.3 45,000 2,000,000
R136c 05h 38m 42.90s −69° 06′ 04.8″ 12.86 WN5h -7.9 51,000 3,000,000
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See also

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References

  1. ↑ Simbad data for RMC 136
  2. ↑ 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.
  3. 1 2 3 4 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:1308.3412v1. doi:10.1051/0004-6361/201321824.
  4. ↑ 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.
  5. ↑ 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.
  6. 1 2 3 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: 180. Bibcode:1998ApJ...493..180M. doi:10.1086/305126.
  7. ↑ 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.
  8. ↑ Banerjee, S.; Kroupa, P.; Oh, S. (2012). "Runaway Massive Stars from R136: Vfts 682 is Very Likely A "Slow Runaway"". The Astrophysical Journal 746: 15. Bibcode:2012ApJ...746...15B. doi:10.1088/0004-637X/746/1/15.
  9. ↑ 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". The Astronomical Journal 104: 1721. Bibcode:1992AJ....104.1721C. doi:10.1086/116355.
  10. 1 2 3 Crowther, P. A.; Dessart, Luc (1998). "Quantitative spectroscopy of Wolf-Rayet stars in HD97950 and R136a - the cores of giant HII regions". Monthly Notices of the Royal Astronomical Society 296 (3): 622. Bibcode:1998MNRAS.296..622C. doi:10.1046/j.1365-8711.1998.01400.x.

Further reading

External links

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