Betelgeuse Dying or Already Gone?
A well-known and very bright star in the constellation Orion may soon explode in a supernova (or already did), according to data released by U.C. Berkeley researchers Tuesday.
The red giant Betelgeuse was so large that it would reach out to Jupiter’s orbit if placed in our own solar system. But now it is smaller by 15 percent over the past decade in a half. It is thought the star may be at the end of its life, or it is changing over from one element to another as nuclear-fusion fuel.
Red giant stars are thought to have short, complicated and violent lifespans. Lasting at most a few million years, they quickly burn out their hydrogen fuel and then switch to helium, carbon and other elements in a series of partial collapses, refuelings and restarts.
"We do not know why the star is shrinking," said Townes’ Berkeley colleague Edward Wishnow. "Considering all that we know about galaxies and the distant universe, there are still lots of things we don’t know about stars, including what happens as red giants near the ends of their lives."
Eventually, the huge star may become a nesting doll of elements, with a mixed iron-nickel core surrounded by onion-like layers of silicon, oxygen, neon, carbon, helium and hydrogen. As the iron fuel runs out, it may explode into a supernova, blasting newly created elements out into the universe and leaving behind a small, incredibly dense neutron star.
But since the star is 600 light-years away, it may have already exploded and we are just getting a glimpse back in time.
