BAT99-7

BAT99-7
Observation data
Epoch J2000      Equinox J2000
Constellation Dorado
Right ascension 04h 55m 34.3416s[1]
Declination −67° 30′ 02.683″[1]
Apparent magnitude (V) 13.81[2]
Characteristics
Evolutionary stage Wolf-Rayet
Spectral type WN4b[3]
U−B color index −0.567[4]
B−V color index −0.35[4]
Astrometry
Proper motion (μ) RA: 1.733[1] mas/yr
Dec.: 0.367[1] mas/yr
Parallax (π)−0.0083 ± 0.0166 mas[1]
Distance50,000 pc
Absolute magnitude (MV)−5.02[3]
Details
Mass25[3] M☉
Radius1.1[3] R☉
Luminosity692,000[3] L☉
Temperature158,500[3] K
Rotational velocity (v sin i)160[5] km/s
Other designations
Brey 6, HD 32109, 2MASS J04553134-6730028
Database references
SIMBADdata

BAT99-7 is a WN-type Wolf-Rayet star located in the Large Magellanic Cloud, in the constellation of Dorado, about 160,000 light years away. The star has a spectrum containing extremely broad emission lines, and is the prototype for the "round line" stars, Wolf-Rayet stars whose spectra are characterized by strong and broad emission lines with round line profiles. The broad emission lines hint at an extremely high temperature of nearly 160,000 Kelvin, which would make it the hottest of all WN stars with known temperatures, as well as an extraordinarily large mass loss rate for a Wolf-Rayet star in the LMC, at 10−4.48 M☉/yr, which means that every 30,200 years, the star loses 1 solar mass worth of mass.[3]

References

  1. ^ 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.
  2. ^ Zacharias, N.; Finch, C. T.; Girard, T. M.; Henden, A.; Bartlett, J. L.; Monet, D. G.; Zacharias, M. I. (2012). "VizieR Online Data Catalog: UCAC4 Catalogue (Zacharias+, 2012)". VizieR On-line Data Catalog: I/322A. Originally Published in: 2012yCat.1322....0Z; 2013AJ....145...44Z. 1322. Bibcode:2012yCat.1322....0Z.
  3. ^ a b c d e f g 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. S2CID 55123954.
  4. ^ a b Zacharias, N.; Finch, C. T.; Girard, T. M.; Henden, A.; Bartlett, J. L.; et al. (July 2012). "VizieR On-line Data Catalog: UCAC4 Catalogue". VizieR On-line Data Catalog: I/322A. 1322. Bibcode:2012yCat.1322....0Z.
  5. ^ Shenar, T.; Hamann, W. -R.; Todt, H. (2014-02-01). "The impact of rotation on the line profiles of Wolf-Rayet stars". Astronomy and Astrophysics. 562: A118. arXiv:1401.2159. Bibcode:2014A&A...562A.118S. doi:10.1051/0004-6361/201322496. ISSN 0004-6361. S2CID 21732510.


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