Iota Canis Majoris

Iota Canis Majoris, Latinized from ι Canis Majoris, is a solitary variable supergiant star in the southern constellation of Canis Major. It is visible to the naked eye with an apparent visual magnitude that varies between +4.36 and +4.40. The distance to this star is approximately 2,500 light years based on spectroscopic measurements. It is drifting further away with a radial velocity of +42 km/s.

Iota Canis Majoris is a massive blue-white B-type supergiant with a stellar classification of B3 Ib. It has been classified as a Beta Cephei type variable star, but the supergiant spectral type and a period of over a day mean it is no longer considered to be of that type. This star is 15 million years old and is spinning with a projected rotational velocity of 30 km/s. It has 14 times more mass and 32 times the radius of the Sun. Iota Canis Majoris is radiating 52,000 times the luminosity of the Sun from its photosphere at an effective temperature of $41.75$.

The star displays a bow shock feature from its interaction with the interstellar medium, but this nebulosity is not aligned with the star's motion through the galaxy.