WR 133

WR 133 is a visually moderately bright Wolf-Rayet star. It is a spectroscopic binary system containing a Wolf-Rayet primary and a class O supergiant secondary. It is in the constellation of Cygnus, lying in the sky at the centre of the triangle formed by β and γ Cygni, near η Cygni. It is the brightest member of the sparse open cluster NGC 6871.

WR 133
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cygnus
Right ascension 20h 05m 57.32445s[1]
Declination +35° 47′ 18.1508″[1]
Apparent magnitude (V) 6.75 - 6.84[2]
Characteristics
Spectral type WN6o + O9I[3]
Apparent magnitude (J) 6.319[4]
Apparent magnitude (K) 6.247[4]
U−B color index −0.77[5]
B−V color index +0.13[5]
Variable type WR[2]
Astrometry
Proper motion (μ) RA: −3.175[1] mas/yr
Dec.: −6.537[1] mas/yr
Parallax (π)0.5380 ± 0.0223[1] mas
Distance6,100 ± 300 ly
(1,860 ± 80 pc)
Absolute magnitude (MV)−3.4 / −5.4[6]
Orbit[3]
Period (P)112.736±0.073 days
Semi-major axis (a)0.7791±0.0024″
Eccentricity (e)0.3646±0.0103
Inclination (i)162.08±1.74°
Semi-amplitude (K1)
(primary)		13.41±2.34 km/s
Semi-amplitude (K2)
(secondary)		32.56±3.98 km/s
Details[3]
WR
Mass9.3±1.6 M☉
Radius3.4±0.5 R☉
Luminosity263,000+68,000
−54,000 L☉
Temperature71,000±5,000 K
O
Mass22.6±3.2 M☉
Radius16.6±1.0 R☉
Luminosity195,000+50,000
−40,000 L☉
Surface gravity (log g)3.30±0.15 cgs
Temperature30,000±1,000 K
Rotational velocity (v sin i)96±10 km/s
Other designations
V1676 Cygni, BD+35°3953, HD 190918, HIP 99002, WDS J20060+3547
Database references
SIMBADdata

WR 133 is one of the brightest Wolf Rayet (WR) stars in the northern hemisphere, slightly brighter than WR 140 which also in Cygnus.[7] The WR star is typically identified as the primary, being more massive, more luminous, and dominating the spectrum. However, the supergiant secondary is more massive and visually brighter. The primary star is a WN5 nitrogen-rich WR star and the secondary has a spectral type of O9I. The orbit is moderately eccentric and has a period of 113 d, which has been determined from the velocity variations observed with the component's spectral lines, mostly from the HeII emission lines at 541.1 nm for the WR primary, and helium and oxygen absorption lines for the primary. This is the first WN-type WR star to have its mass dynamically determined from orbital motion, although the precision is hampered by the nearly face-on orientation of the orbit.[3]

WR 133 is listed as a Wolf-Rayet variable star and has been given the variable star designation V1676 Cyg in the General Catalogue of Variable Stars. Its visual magnitude varies between 6.75 and 6.84.[2]

References
  1. Brown, A. G. A.; et al. (Gaia collaboration). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics (in press). arXiv:2012.01533. doi:10.1051/0004-6361/202039657. S2CID 227254300. Gaia EDR3 record for this source at VizieR.
  2. 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.
  3. Richardson, Noel D.; Lee, Laura; Schaefer, Gail; Shenar, Tomer; Sander, Andreas A. C.; Hill, Grant M.; Fullard, Andrew G.; Monnier, John D.; Anugu, Narsireddy; Claire L Davies; Gardner, Tyler; Lanthermann, Cyprien; Kraus, Stefan; Setterholm, Benjamin R. (2021). "The First Dynamical Mass Determination of a Nitrogen-rich Wolf-Rayet Star using a Combined Visual and Spectroscopic Orbit". arXiv:2101.04232 [astro-ph.SR].
  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. 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.
  6. Massey, P.; Degioia-Eastwood, K.; Waterhouse, E. (2001). "The Progenitor Masses of Wolf-Rayet Stars and Luminous Blue Variables Determined from Cluster Turnoffs. II. Results from 12 Galactic Clusters and OB Associations". The Astronomical Journal. 121 (2): 1050–1070. arXiv:astro-ph/0010654. Bibcode:2001AJ....121.1050M. doi:10.1086/318769.
  7. 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 (1): 2–13. Bibcode:2011MNRAS.418....2F. doi:10.1111/j.1365-2966.2011.19035.x.
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