A “Nasty” Star!
Wolf-Rayet stars represent a final blaze of glory before a doomed massive star finally reaches the end of that long stellar road and explodes in a brilliant and invariably fatal supernova explosion. Massive stars live fast and die young–and Wolf-Rayet stars are very massive, indeed. These stars are at least 20 times more massive than our own relatively small Star, the Sun, and their grand finale is truly a stellar farewell performance when they violently and brilliantly blow themselves to pieces. In May 2015, a team of astronomers using NASA’s Hubble Space Telescope (HST) announced that they have uncovered amazing new clues about a rapidly aging, massive star whose weird behavior has never been observed before in our Milky Way Galaxy. In fact, this elderly, heavy star is so bizarre and unique among the known stellar denizens of the Cosmos that astronomers have nicknamed it Nasty 1, a play on its more dignified catalog name of NaST1–and this nasty star may represent a fleeting transitory stage in the evolution of https://youtube.com/channel/UC5zgCLpojUaU8ZryX9s6CFQ extremely massive stars.
Nasty 1 was first discovered several decades ago, and was identified as a Wolf-Rayet star–a rapidly evolving star that is considerably more massive than our Sun. Wolf-Rayet stars lose their hydrogen-laden outer gaseous layers rapidly, exposing their extremely hot and brilliantly bright helium-burning hearts.
Stars like our Sun maintain a very precious and delicate balance between two eternally warring forces–gravity and radiation pressure. A main-sequence (hydrogen-burning) “normal” star, like our Sun, keeps itself bouncy and fluffy against its own gravity as a result of pressure derived from nuclear fusion. Gravity tries to pull everything in towards the star, while radiation pressure tries to push everything out and away from the star. When the two opposing rivals are about equal, the star is a stable, glaring, roiling ball of mostly seething-hot hydrogen gas that is blissfully fusing heavier atomic elements out of lighter ones. For planets like our Earth, lucky enough to be the happy child of a stable parent-star, this period can continue on and on for billions and billions of years. Our own Sun is still in active mid-life at about 4.56 billion years of age, and it will not “die” for another 5 billion years, or so.