A type of very hot star whose spectrum shows very broad emission lines of helium and hydrogen.
Unusual stars that is very massive (over 40 times the mass of our Sun), extremely hot and very bright. These stars continually eject their outer atmosphere in bubble-like shells of particles and gas (and creating a strong stellar wind). About 200 of these stars are known in the Milky Way; most of these are very far from us.
a very luminous star with a high surface temperature, often with large eruptions and some irregular small light variations (up to about