Sirius (also known as Alpha Canis Majoris or the Dog Star) is the brightest star in the night sky. It is located in the constellation Canis Major. Sirius is almost 25 times brighter than the sun and about twice as massive.
Sirius is actually a binary star; its companion is a white dwarf near the size of the sun called Sirius B. The recording of Sirius dates back to at least ancient Egypt, where it was known as "Sopdet" and was a major feature of the Egyptian calendar. Its first annual heliacal rising signaled the beginning of the flood season for the Nile River Delta.