WR 140

WR 140 is a visually moderately bright Wolf-Rayet star placed within the spectroscopic binary star, SBC9 1232,[11] whose primary star is an evolved spectral class O4-5 star.[11] It is located in the constellation of Cygnus, lying in the sky at the centre of the triangle formed by Deneb, γ Cygni and δ Cygni.

WR 140
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cygnus
Right ascension  20h 20m 27.97608s[1]
Declination +43° 51′ 16.2802″[1]
Apparent magnitude (V) 6.85[2]
Characteristics
Spectral type WC7p + O5[3]
Apparent magnitude (J) 5.547[4]
Apparent magnitude (K) 5.037[5]
U−B color index −0.35[2]
B−V color index +0.40[2]
Variable type WR[6]
Astrometry
Radial velocity (Rv)3.10[7] km/s
Proper motion (μ) RA: −4.653[8] mas/yr
Dec.: −2.047[8] mas/yr
Parallax (π)0.5815 ± 0.0286[8] mas
Distance5,600 ± 300 ly
(1,720 ± 80 pc)
Absolute magnitude (MV)WR: −6.6 - −4.8
O: −6.11 - −5.94[9]
Orbit[9]
Period (P)2,896.35 ± 0.20 days
Semi-major axis (a)8.82 ± 0.05"
(12.6 AU[10])
Eccentricity (e)0.8964+0.0004
−0.0007
Inclination (i)119.6 ± 0.5°
Details
WR
Mass14.9[9] M☉
Luminosity537,000[10] L☉
Temperature70,000[10] K
O
Mass35.9[9] M☉
Radius35[10] R☉
Luminosity1,600,000[10] L☉
Temperature35,000[10] K
Other designations
V1687 Cygni, BD+43° 3571, HD 193793, HIP 100287, SBC9 1232, WDS J20205+4351
Database references
SIMBADdata

WR 140 has been described as the brightest Wolf Rayet star in the northern hemisphere, although WR 133 also in Cygnus is comparably bright.[12] The Wolf-Rayet component is identified as the secondary star, being less massive, less luminous, and probably less visually bright than its primary even though it dominates the spectrum with its broad emission lines.[11] The primary star is an O4-5 star,[11] most likely a giant or supergiant.[9][10] Its current accepted spectroscopic orbit is highly eccentric and has an orbital period of 7.9 ± 0.2 years, which has been determined from the velocity variations observed with the component's spectral lines, mostly from the Balmer absorption lines of the O4-5 primary and C IV emission lines at 465.0 nm. for WR 140.[11] Separation between these two stars varies from 1.3 AU at periastron to 23.9 AU at apastron.[10]

WR 140 is listed as a Wolf-Rayet variable star, and has been given the variable star designation V1687 Cyg in the General Catalogue of Variable Stars, whose visual brightness varies only very slightly.[6] Interest with this WR 140 system is principally observing the infrared light fluctuations during the component's orbit, being extensively studied because of its episodic dust formation.[13] It is now regarded as the prototype colliding-wind binary.[9] Shortly after periastron passage every eight years, the infrared brightness increases dramatically and then slowly drops again over a period of months.[11] Here stellar winds collide with the dust formation created by the stars.[9]

References
  1. Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
  2. Ducati, J. R. (2002). "VizieR On-line Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
  3. Shenavrin, V. I.; Taranova, O. G.; Nadzhip, A. E. (2011). "Search for and study of hot circumstellar dust envelopes". Astronomy Reports. 55: 31. Bibcode:2011ARep...55...31S. doi:10.1134/S1063772911010070.
  4. 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.
  5. Van Der Hucht, K. A. (2006). "New Galactic Wolf-Rayet stars, and candidates. An annex to the VIIth Catalogue of Galactic Wolf-Rayet Stars". Astronomy and Astrophysics. 458 (2): 453. arXiv:astro-ph/0609008. Bibcode:2006A&A...458..453V. doi:10.1051/0004-6361:20065819.
  6. Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
  7. Pourbaix, D.; Tokovinin, A. A.; Batten, A. H.; Fekel, F. C.; Hartkopf, W. I.; Levato, H.; Morrell, N. I.; Torres, G.; Udry, S. (2004). "SB9: The ninth catalogue of spectroscopic binary orbits". Astronomy and Astrophysics. 424 (2): 727. arXiv:astro-ph/0406573. Bibcode:2004A&A...424..727P. doi:10.1051/0004-6361:20041213.
  8. 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.
  9. Monnier, J. D.; Zhao, Ming; Pedretti, E.; Millan-Gabet, R.; Berger, J.-P.; Traub, W.; Schloerb, F. P.; Ten Brummelaar, T.; McAlister, H.; Ridgway, S.; Sturmann, L.; Sturmann, J.; Turner, N.; Baron, F.; Kraus, S.; Tannirkulam, A.; Williams, P. M. (2011). "First Visual Orbit for the Prototypical Colliding-wind Binary WR 140". The Astrophysical Journal Letters. 742: L1. arXiv:1111.1266. Bibcode:2011ApJ...742L...1M. doi:10.1088/2041-8205/742/1/L1.
  10. Williams, Peredur (2011). "Results from the 2009 campaign on WR 140". Société Royale des Sciences de Liège. 80: 595. Bibcode:2011BSRSL..80..595W.
  11. Pourbaix, D.; Udry, S.; et al. (2004). "VizieR Online Data Catalog: SB9: 9th Catalogue of Spectroscopic Binary Orbits (Pourbaix+ 2004-2014)". VizieR On-line Data Catalog: B/sb9. Originally Published in: 2004A&A...424..727P. 1. arXiv:astro-ph/0406573. Bibcode:2004A&A...424..727P. doi:10.1051/0004-6361:20041213.
  12. Fahed, R.; Moffat, A. F. J.; Zorec, J.; Eversberg, T.; Chené, A. N.; Alves, F.; Arnold, W.; Bergmann, T.; Corcoran, M. F.; Correia Viegas, N. G.; Dougherty, S. M.; Fernando, A.; Frémat, Y.; Gouveia Carreira, L. F.; Hunger, T.; Knapen, J. H.; Leadbeater, R.; Marques Dias, F.; Martayan, C.; Morel, T.; Pittard, J. M.; Pollock, A. M. T.; Rauw, G.; Reinecke, N.; Ribeiro, J.; Romeo, N.; Sánchez-Gallego, J. R.; Dos Santos, E. M.; Schanne, L.; et al. (2011). "Spectroscopy of the archetype colliding-wind binary WR 140 during the 2009 January periastron passage". Monthly Notices of the Royal Astronomical Society. 418: 2. Bibcode:2011MNRAS.418....2F. doi:10.1111/j.1365-2966.2011.19035.x.
  13. Moffat, A. F. J.; Shara, M. M. (1986). "Photometric variability of a complete sample of northern Wolf-Rayet stars". Astronomical Journal. 92: 952. Bibcode:1986AJ.....92..952M. doi:10.1086/114227.
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