A Wolf-Rayet star is a hot, massive star that is in a very short-lived evolutionary stage. The name comes from the two French astronomers who first identified this type of star: Charles Wolf and Georges Rayet.
Wolf-Rayet stars are about 20 times more massive than our Sun and have surface temperatures of around 30,000 Kelvin. They are also extremely luminous, with 100 to 1,000 times the luminosity of our Sun. These characteristics make them some of the most visually stunning objects in the night sky.
Despite their brilliance, Wolf-Rayet stars are actually in their death throes. They are losing mass at an astonishing rate – up to 10 million times faster than our Sun – due to strong stellar winds blowing material away from their surfaces. This mass loss means that they are burning through their fuel supply much faster than less massive stars like our Sun. As a result, they only live for a few million years before running out of fuel and exploding as supernovae.
The high mass loss rates of Wolf-Rayet stars make them important contributors to the chemical enrichment of the Universe. Their strong winds blow heavy elements such as carbon and oxygen into the interstellar medium, where they can be used by subsequent generations of stars and planets. In fact, many of the elements we find on Earth were created in previous generations of dying stars like Wolf-Rayets!