W Canis Majoris

W Canis Majoris
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Canis Major
Right ascension 07h 08m 03.43652s[1]
Declination 11° 55 23.7977[1]
Apparent magnitude (V) 6.35 - 7.90[2]
Characteristics
Spectral type C6,3(N)[2]
B−V color index +2.55[3]
Variable type Lb[2][4]
Astrometry
Radial velocity (Rv)23.00[5] km/s
Proper motion (μ) RA: 5.55[1] mas/yr
Dec.: 2.74[1] mas/yr
Parallax (π)0.39 ± 0.52[1] mas
Distance1,444 - 1,450[6] ly
(443 - 445[6] pc)
Details
Radius234[6] R
Luminosity3,560[6] L
Surface gravity (log g)0.0[6] cgs
Temperature2,900[6] K
Other designations
W CMa, HIP 34413, HD 54361, SAO 152427
Database references
SIMBADdata

W Canis Majoris is a carbon star in the constellation Canis Major. A cool star, it has a surface temperature of around 2,900 K and a radius 234 times that of the sun, with a bolometric absolute magnitude of 4.13 and distance estimated at 443 or 445 parsecs (1444-1450) light-years based on bolometric magnitude or radius.

W CMa is classified as an irregular star. Detailed analyses have found only very weak and probably spurious periods of approximately a month.[4] It is a carbon star, an asymptotic giant branch star where carbon and s-process elements have been dreged up to the surface during thermal pulses of the helium burning shell.[7]

References

  1. 1 2 3 4 5 Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
  2. 1 2 3 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. Alksnis, A.; Balklavs, A.; Dzervitis, U.; Eglitis, I. (1998). "Absolute magnitudes of carbon stars from HIPPARCOS parallaxes". Astronomy and Astrophysics. 338: 209. Bibcode:1998A&A...338..209A.
  4. 1 2 Percy, J. R.; Terziev, E. (2011). "Studies of "Irregularity" in Pulsating Red Giants. III. Many More Stars, an Overview, and Some Conclusions". The Journal of the American Association of Variable Star Observers. 39: 1. Bibcode:2011JAVSO..39....1P.
  5. Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065.
  6. 1 2 3 4 5 6 van Belle, Gerard T.; Paladini, Claudia; Aringer, Bernhard; Hron, Josef; et al. (2013). "The PTI Carbon Star Angular Size Survey: Effective Temperatures and Non-sphericity". The Astrophysical Journal. 775 (1): article id. 45, 19 pp. arXiv:1307.6585Freely accessible. Bibcode:2013ApJ...775...45V. doi:10.1088/0004-637X/775/1/45.
  7. Herwig, Falk; Austin, Sam M. (2004). "Nuclear Reaction Rates and Carbon Star Formation". The Astrophysical Journal. 613: L73. arXiv:astro-ph/0408394Freely accessible. Bibcode:2004ApJ...613L..73H. doi:10.1086/424872.
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