Blue Supergiant Stars

Blue supergiant stars are typically characterized by an O-Type spectrum, or a B-type spectrum for those classified as blue-white.

Deneb

Deneb is a blue-white supergiant star which forms the tail of the swan in the constellation Cygnus, or the top of the cross if the constellation is referred to as the Northern Cross. It's companions in the Summer Triangle are Vega and Altair.

Blue-white stars are typically characterized by a B-type spectrum.

Sk-69202, Progenitor of SN 1987A

It was fortunate that the star which produced Supernova 1987A was a known star, a blue supergiant star which had been catalogued as SK-69202. It presumed to have a mass of about 20 solar masses.

Blue supergiant stars are typically characterized by an O-Type spectrum.