Wolf-Rayet star, any of a class of extremely hot, white stars having peculiar spectra thought to indicate either great turbulence within the star or a steady, voluminous ejection of material. A typical Wolf-Rayet star is several times the diameter of the Sun and thousands of times more luminous. Only a few hundred are known, located mostly in the spiral arms of the Milky Way Galaxy. The type was first distinguished in 1867 by the French astronomers Charles-Joseph-Étienne Wolf and Georges-Antoine-Pons Rayet.