A Hypernova in Betelgeuse?
Betelgeuse, one of the brightest stars in the sky, could burst into its supernova phase and become as bright as a full moon - and last for as long as a year. The massive star is visible in the winter sky over most of the world as a bright, reddish star, could explode as a supernova anytime within the next 100,000 years.
The red giant Betelgeuse, once so large it would reach out to Jupiter’s orbit if placed in our own solar system, has shrunk by 15 percent over the past decade in a half, although it’s just as bright as it’s ever been.
“To see this change is very striking,” said retired Berkeley physics professor Charles Townes, who won the 1964 Nobel Prize for inventing the laser. “We will be watching it carefully over the next few years to see if it will keep contracting or will go back up in size.” Betelgeuse, whose name derives from Arabic, is easily visible in the constellation Orion. It gave Michael Keaton’s character his name in the movie “Beetlejuice” and was the home system of Galactic President Zaphod Beeblebrox in “The Hitchhiker’s Guide to the Galaxy.”
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.
Betelgeuse, which is thought to be reaching the end of its lifespan, may be experiencing one of those collapses as it switches from one element to another as nuclear-fusion fuel. “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.”
If Betelgeuse goes nova, it could offer Earth’s astronomers an up close look at how supernovae evolve and the physics that governs how they work. The problem is that it is not clear when that will happen. While stories have been circulating that the star could explode in 2012, the odds of that are actually quite small. Betelgeuse may explode tomorrow night, or it may not go nova until the year 100,000 A.D. It’s impossible to know.