Sirius the brightest star in the sky, south of the celestial equator in the constellation Canis Major. It is a binary star with a dim companion, which is a white dwarf. Sirius is conspicuous in the winter sky of the northern hemisphere, apparently following on the heels of the hunter Orion, and is also known as the Dog Star. It was important to the ancient Egyptians, as its heliacal rising coincided with the season of flooding of the Nile.

Sirius (Alpha Canis Majoris) Brightest star visible from Earth, in the northern constellation of Canis Major. Its luminosity is 23 times that of the Sun.