A massive, evolved variable star with a luminosity around 105–106 times that of the Sun, close to the Eddington limit. All hypergiants are unstable, exhibiting high mass loss, sometimes in violent outbursts. Two broad classes of hypergiant are identified: S Doradus stars and cool hypergiants. The latter have spectral types ranging from late A to M, and may represent the evolutionary stage before becoming S Doradus variables.
Subjects: Astronomy and Astrophysics.