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.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| 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 mas[1] |
| Distance | 50,000 pc |
| Details | |
| Mass | 7.7[3] M☉ |
| Radius | 0.47[3] R☉ |
| Luminosity | 158,500[3] L☉ |
| Temperature | 170,000[3] K |
| Other designations | |
Brey 93, 2MASS J05393430-6844091 | |
| Database references | |
| SIMBAD | data |
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
editAnalysis 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
edit- ^ a b c d e Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- ^ a b c Bonanos, A. Z.; Massa, D. L.; Sewilo, M.; Lennon, D. J.; Panagia, N.; Smith, L. J.; Meixner, M.; Babler, B. L.; Bracker, S.; Meade, M. R.; Gordon, K. D.; Hora, J. L.; Indebetouw, R.; Whitney, B. A. (2009-10-01). "Spitzer SAGE Infrared Photometry of Massive Stars in the Large Magellanic Cloud". The Astronomical Journal. 138 (4): 1003–1021. arXiv:0905.1328. Bibcode:2009AJ....138.1003B. doi:10.1088/0004-6256/138/4/1003. ISSN 0004-6256.
- ^ a b c d e f g Tramper, F.; Straal, S. M.; Sanyal, D.; Sana, H.; de Koter, A.; Gräfener, G.; Langer, N.; Vink, J. S.; de Mink, S. E.; Kaper, L. (2015-09-01). "Massive stars on the verge of exploding: the properties of oxygen sequence Wolf-Rayet stars". Astronomy and Astrophysics. 581: A110. arXiv:1507.00839. Bibcode:2015A&A...581A.110T. doi:10.1051/0004-6361/201425390. ISSN 0004-6361.
- ^ Sanduleak, N. (1971-03-01). "On Stars Having Strong O VI Emission". The Astrophysical Journal. 164: L71. Bibcode:1971ApJ...164L..71S. doi:10.1086/180694. ISSN 0004-637X.