Here the full article: http://en.wikipedia.org/wiki/VY_Canis_Majoris

VY Canis Majoris (VY CMa) is a red hypergiant star located in the constellation Canis Major. It is the largest known star and also one of the most luminous known. It is located about 1.5 kiloparsecs (or 5,000 light-years) from Earth.