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Sirius is actually two stars, a binary system comprising of Sirius A (The Dog Star) a white main-sequence star and Sirius B (The Pup-Star), a white dwarf star.
In Britain, Sirius is best viewed in late winter and appears as a very bright blue-white star south-east of the constellation Orion and is one of three stars which form the asterism The Winter Triangle.
[1] Brilliant Stars