Wolf Rayet (pronounced /wolf ray-ay/) stars are large blue stars that...
Wolf-Rayet stars (often referred to as WR stars) are evolved, massive stars (over 20 solar masses), which are losing mass rapidly by means of a very strong stellar wind, with speeds up to 2000 km/s. While our own Sun loses approximately 10−14 solar masses every year, Wolf-Rayet stars typically lose 10−5 solar masses a year.
Wolf-Rayet stars are very hot, with surface temperatures in the range of 25,000 K to 50,000 K. It is believed that the star in the galaxy NGC 2770 that exploded into a supernova on January 9, 2008 — SN 2008D, the first supernova ever observed in the act of exploding — was a Wolf-Rayet star. More...
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WR 104
WR 104 is a Wolf-Rayet star located 8000 light years from Earth. It is a binary star with a class OB companion. The stars have an orbital period of 220 days and the interaction between their stellar winds produce a spiral "pinwheel" outflow pattern over 200 AU long. The spiral is composed of dust that would normally be prevented from forming by WR 104's intense radiation were it not for the star's companion. The region where the stellar wind from the two massive stars interacts compresses the material enough for the dust to form, and the rotation of the system causes the spiral-shaped pattern.
WR 104's rotational axis is aligned within 16° of Earth. This could have potential implications to the effects of WR 104's eventual supernova, since these explosions often produce jets from their rotational poles. It is possible that WR 104 may even produce a gamma-ray burst, though it is not possible to predict with certainty at this time. More...
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Hypernovae are superbright novae...
Hypernova (pl. hypernovae) refers to an exceptionally large star that collapses at the end of its lifespan—for example, a collapsar, or a large supernova. Until the 1990s, it referred specifically to an explosion with an energy of over 100 supernovae (1046 joules); such explosions were proposed to explain the origin of exceptionally bright gamma ray bursts. An extensive sky search found several apparent hypernova remnants, but too few to support the hypothesis. More...