Omega Canis Majoris

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Template:Short description

ω Canis Majoris
Template:Location mark
Location of ω Canis Majoris (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Canis Major
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 3.60 - 4.18[2]
Characteristics
Spectral type B2.5Ve[3]
U−B Template:Engvar −0.73[4]
B−V Template:Engvar −0.14[4]
Variable type γ Cas[2]
Astrometry
Proper motion (μ) RA: −11.88[1] mas/yr
Dec.: +6.87[1] mas/yr
Parallax (π)3.58±0.17 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)−3.21[5]
Details
MassScript error: No such module "val".[6] Template:Solar mass
Radius6.2[7] Template:Solar radius
Luminosity13,081[8] Template:Solar luminosity
Surface gravity (log g)3.5[9] cgs
Temperature21,878[9] K
Rotational velocity (v sin i)80[10] km/s
AgeScript error: No such module "val".[6] Myr
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Template:Odlist[11]
Database references
SIMBADdata

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Omega Canis Majoris, Latinized from ω Canis Majoris, is a solitary,[12] blue-white-hued star in the equatorial constellation of Canis Major. It is visible to the naked eye with an apparent visual magnitude of about 4. Based upon an annual parallax shift of just 3.58 mas as seen from Earth,[1] this system is located roughly 910 light-years from the Sun.

File:OmegaCMaLightCurve.png
A visual band light curve for Omega Canis Majoris, adapted from Štefl et al. (2003)[13]

This star has a stellar classification of B2.5Ve, indicating it is a main sequence Be star, although it has also been classified as a subgiant.[14] One of the most observed Be stars of the Southern Hemisphere,[15] Omega Canis Majoris is classified as a Gamma Cassiopeiae-type variable star.[2] Both the luminosity and the radial velocity vary with a primary cyclical period of 1.372 days.[16] The variation in brightness, ranging from magnitude +3.60 to +4.18,[2] shows changes over time, which suggests there are two overlapping periods of 1.37 and 1.49 days. The star also undergoes transient periodicities following outbursts.[17][10]

This is a massive star with ten[6] times the mass of the Sun and 6.2[7] times the Sun's radius. At an estimated age of 22.5 million years,[6] it is radiating 13,081[8] times the Sun's luminosity from its photosphere at an effective temperature of 21,878 K.[9] The star is being viewed nearly pole on, so the measured projected rotational velocity of 80 km/s is only a fraction of the true equatorial velocity, estimated as 350 km/s. It is surrounded by a symmetric circumstellar decretion disk of material that is being heated by the star, which in turn is inserting emission lines into the combined spectrum.[10]

References

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External links

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Template:Stars of Canis Major