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
A high mass star (10 to 50 solar masses) showing emission lines of helium, and hydrogen or carbon.
One of a class of very luminous, very hot (as high as 50,000 K) stars whose spectra have broad emission lines (mainly He I and He II), which are presumed to originate from material ejected from the star at very high (~ 2000 km s-1 ) velocities. Some W-R spectra show emission lines due to carbon (WC stars); others show emission lines due to nitrogen (WN stars). (Hiltner and Schild classification: WN-A, narrow lines; WN-B, broad lines.) [H76
Wolf-Rayet stars (often referred to as WR stars) are evolved, massive stars (over 20 solar masses), and are losing their mass rapidly by means of a very strong stellar wind, with speeds up to 2000 km/s. While our own sun loses 10-14 of its own mass on a yearly basis, a Wolf-Rayet star loses 10-5 solar masses a year. These stars are also very hot: their temperature are in the range of 25,000 K to 50,000 K.