BAT99-98

BAT99-98

Observation data
Epoch J2000      Equinox J2000
Constellation Dorado
Right ascension 05h 38m 39.147s
Declination −69° 06′ 21.20″
Apparent magnitude (V) 13.70 [1]
Characteristics
Evolutionary stage Wolf-Rayet star
Spectral type WN6
B−V color index -0.10[2]
Astrometry
Distance165,000 ly
(50,600 pc)
Absolute magnitude (MV)-8.11[1]
Absolute bolometric
magnitude (Mbol)		-12.0
Details
Mass226[1] M☉
Radius37.5[1] R☉
Luminosity5,000,000 [1] L☉
Luminosity (visual, LV)141,000 [1] L☉
Temperature45,000 [1] K
Metallicity~0.4 Z☉
Age~2 Myr
Other designations
Brey 79, Cl* NGC 2070 MEL J, SSTISAGEMC J053839.14-690621.2, M2002 LMC 171429, BAT99 98, LMC AB 12, UCAC3 42-32386, P93 691, Cl* NGC 2070 MEL 49, 2MASS J05383914-6906211, UCAC4 105-014273
Database references
SIMBADdata

BAT99-98 is a star in the Large Magellanic Cloud. It is located near the R136 cluster in the 30 Doradus nebula. At 226 M☉ and 5,000,000 L☉ it is the second most massive and the fourth most luminous star known. [1]

Observations

A 1978 survey carried out by J. Melnick covered the 30 Doradus region and found six new W-R stars, all belonging to the WN sequence. Out of 12 objects, BAT99-98 was the seventh star observed. It was catalogued as Cl* NGC 2070 MEL J. The survey observed stars that were above magnitude 14 and that were within two arcminutes of the centre of the 30 Doradus nebula. BAT99-98 was found to have an apparent magnitude of 12 and a spectral type of WN5. [3]

Characteristics

The star is located near the R136 cluster and shares similar mass-luminosity properties to the massive stars in R136. It is estimated that at its birth that the star held 250M☉ and has since lost 20M☉. [1] It sheds a large amount of mass through a stellar wind that moves at 1600km/s.[1] The star has a surface temperature of 45,000 K and a luminosity of 5,000,000L☉. Although the star is very luminous, it only has a visual luminosity of 141,000L☉. It has a metallicity of ~0.4 Z☉ which corresponds a fraction of 0.004 of its total composition. It is classified as a WN6 star.

Fate

The future of BAT99-98 depends on its mass loss. It is thought that stars this massive will never lose enough mass to avoid a catastrophic end. The result is likely to be a supernova, hypernova, gamma-ray burst, or perhaps almost no visible explosion, and leaving behind a black hole or neutron star. The exact details depend heavily on the timing and amount of the mass loss, with current models not fully reproducing observed stars, but the most massive stars in the local universe are expected to produce type Ib or Ic supernovae, sometimes with a gamma-ray burst, and leave behind a black hole.[4]

See also

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 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.
  2. ↑ 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". arXiv:1308.3412v1 [astro-ph.SR].
  3. ↑ Melnick, J. (1978). "More Wolf-Rayet stars in 30 Doradus.". Astronomy and Astrophysics Supplement Series 34: 383–385. Bibcode:1978A&AS...34..383M.
  4. ↑ Woosley, S. E.; Heger, A. (2015). "The Deaths of Very Massive Stars". Very Massive Stars in the Local Universe. Astrophysics and Space Science Library 412: 199. arXiv:1406.5657. Bibcode:2015ASSL..412..199W. doi:10.1007/978-3-319-09596-7_7. ISBN 978-3-319-09595-0.