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. 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. 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. 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.