VY Canis Majoris
VY Canis Majoris is an extreme oxygen-rich red hypergiant or red supergiant and pulsating variable star 1.2 kiloparsecs from the Solar System in the slightly southern constellation of Canis Major. It is one of the largest known stars, one of the most luminous and massive red supergiants, and one of the most luminous stars in the Milky Way. No evidence has been found that it is part of a multiple star system. Its great infrared excess makes it one of the brightest objects in the local part of the galaxy at wavelengths of 5 to 20 microns and indicates a dust shell or heated disk. It is about 17±8 times the mass of the Sun. It is surrounded by a complex asymmetric circumstellar envelope caused by its mass loss. It produces strong molecular maser emission and was one of the first radio masers discovered. VY CMa is embedded in the large molecular cloud Sh2-310, a large, quite local star-forming H II region—its diameter: 480 arcminutes or 681 ly.
