Astronomy:BAT99-123

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Short description: Wolf-Rayet star in the constellation Dorado
BAT99-123
Observation data
Equinox J2000.0]] (ICRS)
Constellation Dorado
Right ascension  05h 39m 34.302s[1]
Declination −68° 44′ 09.16″[1]
Apparent magnitude (V) 15.204[2]
Characteristics
Evolutionary stage Wolf-Rayet
Spectral type WO3[3]
U−B color index −1.335[2]
B−V color index 0.422[2]
Astrometry
Proper motion (μ) RA: 1.718[1] mas/yr
Dec.: 0.876[1] mas/yr
Parallax (π)−0.0198 ± 0.055[1] mas
Distance50,000 pc
Details
Mass7.7[3] M
Radius0.47[3] R
Luminosity158,500[3] L
Temperature170,000[3] K
Other designations
Brey 93, 2MASS J05393430-6844091
Database references
SIMBADdata

BAT99-123, also known as Brey 93, is a rare WO-type (oxygen sequence) Wolf–Rayet star located in the Large Magellanic Cloud, about 160,000 light years away in Dorado. BAT99-123 was the first WO star discovered in the LMC, and only 3 are known to exist in the galaxy, the other two being LH 41-1042 and LMC195-1.

BAT99-123 was first discovered in 1970, and identified as a star with strong OVI emission in 1971, alongside other WO stars like WR 102, WR 142 and SMC AB8.[4] Most stars with strong OVI emission known at the time were central stars of planetary nebulae.

Properties

Analysis of BAT99-123's spectrum reveals a surface temperature of 170,000 K. Assuming a distance of 50.12 kpc, or about 163,500 light years, BAT99-123's luminosity is about 158,500 L, corresponding to a radius of 0.47 R. BAT99-123's strong stellar wind, which has a very high terminal velocity of 3300 km/s, causes it to lose 10-5.14 M☉ (about 7.24×10−6 M) a year.[3]

WO-type Wolf-Rayet stars are very very close to the end of their lives. BAT99-123 is predicted to explode in a type Ic supernova in about 7,000 years. By then, it's predicted to have a mass of 7.7 M☉, much lower than its initial mass which was likely a few dozen solar masses.[3] It likely has a similar mass right now as its stellar wind will not change the mass much in this timescale.

References

  1. Jump up to: 1.0 1.1 1.2 1.3 1.4 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  2. Jump up to: 2.0 2.1 2.2 Bonanos, A. Z.; Massa, D. L.; Sewilo, M.; Lennon, D. J.; Panagia, N.; Smith, L. J.; Meixner, M.; Babler, B. L. et al. (2009-10-01). "Spitzer SAGE Infrared Photometry of Massive Stars in the Large Magellanic Cloud". The Astronomical Journal 138 (4): 1003–1021. doi:10.1088/0004-6256/138/4/1003. ISSN 0004-6256. Bibcode2009AJ....138.1003B. https://ui.adsabs.harvard.edu/abs/2009AJ....138.1003B. 
  3. Jump up to: 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Tramper, F.; Straal, S. M.; Sanyal, D.; Sana, H.; de Koter, A.; Gräfener, G.; Langer, N.; Vink, J. S. et al. (2015-09-01). "Massive stars on the verge of exploding: the properties of oxygen sequence Wolf-Rayet stars". Astronomy and Astrophysics 581: A110. doi:10.1051/0004-6361/201425390. ISSN 0004-6361. Bibcode2015A&A...581A.110T. https://ui.adsabs.harvard.edu/abs/2015A&A...581A.110T. 
  4. Sanduleak, N. (1971-03-01). "On Stars Having Strong O VI Emission". The Astrophysical Journal 164: L71. doi:10.1086/180694. ISSN 0004-637X. Bibcode1971ApJ...164L..71S. https://ui.adsabs.harvard.edu/abs/1971ApJ...164L..71S.