15 Canis Majoris is a variable star in the southern constellation of Canis Major, located roughly 1,200 light years away from the Sun. It has the variable star designation EY Canis Majoris; 15 Canis Majoris is the Flamsteed designation. The star is visible to the naked eye as a faint, blue-white hued star with a baseline apparent visual magnitude of +4.82. It is moving away from the Earth with a heliocentric radial velocity of 28 km/s.
This is a B-type supergiant star with a stellar classification of B1 Ib. It is classified as a Beta Cephei type variable star and its brightness varies from magnitude +4.79 down to +4.84 with a period of 0.18457day. The star has 12.8 times the mass of the Sun and 6.8 times the Sun's radius. It is radiating 20,000 times the luminosity of the Sun from its photosphere at an effective temperature of 26,100 K.