BAT99-7

Last updated
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]
Distance 50,000  pc
Absolute magnitude  (MV)−5.02 [3]
Details
Mass 25 [3]   M
Radius 1.1 [3]   R
Luminosity 692,000 [3]   L
Temperature 158,500 [3]   K
Rotational velocity (v sin i)160 [5]  km/s
Other designations
Brey 6, HD 32109, 2MASS  J04553134-6730028
Database references
SIMBAD data

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]

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References

  1. 1 2 3 4 5 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. 1 2 3 4 5 6 7 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. 1 2 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.