WR 114

WR 114 is a Wolf-Rayet star in the constellation of Scutum. It is an early type star of the carbon sequence (WCE) classified as WC5.

WR 114
Observation data
Epoch J2000      Equinox J2000
Constellation Scutum
Right ascension 18h 23m 16.34s[1]
Declination −13° 43′ 26.2″[1]
Apparent magnitude (V) 12.02[2]
Characteristics
Evolutionary stage Wolf-Rayet
Spectral type WC5[3]
U−B color index +0.54[2]
B−V color index +0.97[2]
Astrometry
Proper motion (μ) RA: 0.307[4] mas/yr
Dec.: −1.931[4] mas/yr
Parallax (π)0.4500 ± 0.0369[4] mas
Distance7,200 ± 600 ly
(2,200 ± 200 pc)
Absolute magnitude (MV)−4.08[3]
Details[3]
Mass13.1+1.3
−1.0 M☉
Radius2.68 R☉
Luminosity245,000 L☉
Temperature79,000 K
Other designations
HD 169010, GSC 05702-01056, 2MASS J18231633-1343261, WR 114
Database references
SIMBADdata

Companion

WR 114 is listed in the Catalogue of galactic Wolf Rayet stars as a possible binary system with an OB companion, but more recent studies have not confirmed this and it is now considered a single WC5 star. No x-rays have been detected from WR 114, which would be expected by a close hot companion.[5][6]

Properties

The modelled temperature as a single star is 79,000 K, but this is an arbitrary temperature. A Wolf-Rayet star consists of a dense "core", with its surface defined as the sonic point, and a surrounding optically dense wind. The observed radiation from the star is entirely generated at different layers within the wind. The properties of a Wolf Rayet star are typically reported at an "inner boundary" of the wind, arbitrarily set at an optical depth of 20. The radius of this inner boundary in WR 114 is 2.51 R☉. The sonic point of WR 114 lies at about optical depth 60. At this level the temperature is much hotter. Another common definition for the surface of a star is at optical depth 2/3. For WR 114, this is at about 3.2 R☉ and the corresponding temperature is around 65,000 K. The luminosity is around 245,000 L☉ due to the extreme temperature, with most of this emitted as ultraviolet radiation.[3][7]

The stellar wind from WR 114 is powered by the high temperature and luminosity to a speed of 2,000 km/s.[6] It is calculated to have a current mass of 13 M☉ and to be losing this mass at three millionths of M☉ per year.[3]

RAFGL 2139
Main article: RAFGL 2139

WR 114 is about 45" from another luminous star of similar brightness. RAFGL 2139 is a red supergiant about 6,500 light years away. At this distance, the projected separation between the two stars would be 0.43 parsecs. WR 114 is listed in the Catalogue of galactic Wolf Rayet stars at around 6,500 light years, but more recent modelling estimates it to be brighter and hence probably more distant. RAFGL 2139 is a runaway with a visible bow shock and it is thought that a Wolf-Rayet star less than half a parsec away would disrupt the bow shock. It is still speculated that the two stars may have a common origin.[8]

References
  1. Cutri, R. M.; Skrutskie, M. F.; Van Dyk, S.; Beichman, C. A.; Carpenter, J. M.; Chester, T.; Cambresy, L.; Evans, T.; Fowler, J.; Gizis, J.; Howard, E.; Huchra, J.; Jarrett, T.; Kopan, E. L.; Kirkpatrick, J. D.; Light, R. M.; Marsh, K. A.; McCallon, H.; Schneider, S.; Stiening, R.; Sykes, M.; Weinberg, M.; Wheaton, W. A.; Wheelock, S.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". VizieR On-line Data Catalog: II/246. Originally Published in: 2003yCat.2246....0C. 2246. Bibcode:2003yCat.2246....0C.
  2. Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237: 0. Bibcode:2002yCat.2237....0D.
  3. Sander, A. A. C.; Hamann, W.-R.; Todt, H.; Hainich, R.; Shenar, T.; Ramachandran, V.; Oskinova, L. M. (2019). "The Galactic WC and WO stars". Astronomy & Astrophysics. 621: A92. arXiv:1807.04293. Bibcode:2019A&A...621A..92S. doi:10.1051/0004-6361/201833712. S2CID 67754788.
  4. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  5. Ignace, R.; Oskinova, L. M.; Pollock, A. M. T.; Brown, J. C.; Hamann, W.-R. (2002). "X-rays from Wolf-Rayet Stars". American Astronomical Society. 201: 33.08. Bibcode:2002AAS...201.3308I.
  6. Oskinova, L. M.; Ignace, R.; Hamann, W.-R.; Pollock, A. M. T.; Brown, J. C. (2003). "The conspicuous absence of X-ray emission from carbon-enriched Wolf-Rayet stars". Astronomy and Astrophysics. 402 (2): 755–766. arXiv:astro-ph/0303025. Bibcode:2003A&A...402..755O. doi:10.1051/0004-6361:20030300. S2CID 9755058.
  7. Gräfener, G.; Vink, J. S. (2013). "Stellar mass-loss near the Eddington limit. Tracing the sub-photospheric layers of classical Wolf-Rayet stars". Astronomy & Astrophysics. 560: A6. arXiv:1309.6236. Bibcode:2013A&A...560A...6G. doi:10.1051/0004-6361/201321914. S2CID 118385793.
  8. Gvaramadze, V. V.; Menten, K. M.; Kniazev, A. Y.; Langer, N.; MacKey, J.; Kraus, A.; Meyer, D. M.-A.; Kamiński, T. (2014). "IRC -10414: A bow-shock-producing red supergiant star". Monthly Notices of the Royal Astronomical Society. 437 (1): 843. arXiv:1310.2245. Bibcode:2014MNRAS.437..843G. doi:10.1093/mnras/stt1943. S2CID 118416927.
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