Magnitude 3.47 | Constellation Canis Major | |
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Sigma Canis Majoris (σ CMa, σ Canis Majoris) is a star in the southern constellation of Canis Major. It is approximately 1,120 light-years (340 parsecs) from Earth and has an average apparent visual magnitude of +3.41.
σ CMa is a supergiant star with a stellar classification of M1.5 Iab. This is a type of star that is in the late stages of its evolution, having consumed the hydrogen at its core and ballooned out to 420 times the Sun's radius. At 1.95 Astronomical Units, this radius is nearly double the average distance of the Earth from the Sun. It is currently radiating about 32,000 times the luminosity of the Sun from its outer envelope at an effective temperature of around 3,877 K. This gives it the cool orange-red hue of an M-type star.
It is classified as an irregular variable star and its brightness varies from magnitude +3.43 to +3.51. The magnetic field of this star has a strength below 1 G. It is suspected of being a member of the Collinder 121 stellar association of co-moving stars, but this is disputed.
Culture signification
The indigenous Boorong people of northwestern Victoria saw it as Unurgunite, flanked by his wives (Epsilon and Delta Canis Majoris).