If Betelgeuse Went Supernova Soon

Drakkith

It will take approximately 600 years for the light to reach Earth once Betelgeuse goes supernova. We cannot predict when it will happen to an accuracy greater than a few million years currently. Hopefully as it approaches we will see fluctuations or something that will tell us it's about to happen.

phyzguy

I think we know more accurately than a few million years. Betelgeuse has already expanded into a red supergiant, which means it has exhausted the hydrogen in its core and moved on to the helium burning phase and possibly beyond. In a star the mass of Betelgeuse (about 20 times the mass of the sun), this phase only lasts on the order of a hundred thousand years. So it should blow within the next few hundred thousand years, possibly tomorrow.

Yes, it's true it will take the light 600 years to reach us after it blows, but it might have blown 599 years, 364 days ago, so we could see it go off tomorrow.

In terms of how it would increase our knowledge of supernovae, it would have a huge impact. Here are two ways. First, since we have studied Betelgeuse extensively, we know a lot about it before it goes off. There are only a few supernovae where we have information on the star before it blew - usually we only find them when they explode. So this would help a lot to refine the models of which types of stars give rise to which types of supernovae. Second, we would learn a lot about the core collapse from the neutrino emissions, which come directly from the core. For SN1987A, we measured ~25 neutrinos here on Earth when it went off. But because Betelgeuse is so much closer, and because the neutrino detectors are so much better than they were in 1987, we would measure many thousands of neutrinos. This would give us neutrino energy spectra and neutrino light curves, which would tell us a lot about the details of the explosion as the core collapses. The light we see comes from the cloud of expanding gas far outside the actual explosion, but the neutrinos 'free stream' directly out from the core collapse itself.

I hope it (or another star in our galaxy) goes off in my lifetime. As has been said, the last one in our galaxy was in 1604, so we are 'due'.

BTW, I have an astronomer friend who has nightmares that Betelgeuse will go off while his telescope is down for maintenance!

Drakkith

Thanks Phyz.

Ravi Mandavi

Guys what i have noticed that pic by shisikabob is highlighted rigel insted of betalgeus

Drakkith

No, it correctly shows Betelgeuse. Rigel is at the bottom right of the constellation and makes up one of the legs/feet.

Ravi Mandavi

Ya, i was misguided i thought it was inverted and i was asuming that its legs were upward but now its clear

Daniel Batt

This article from HuffPo suggests a much greater impact of it going supernova.

"Dr. Brad Carter, Senior Lecturer of Physics at the University of Southern Queensland, outlined the scenario to news.com.au. Betelgeuse, one of the night sky's brightest stars, is losing mass, indicating it is collapsing. It could run out of fuel and go super-nova at any time.

"When that happens, for at least a few weeks, we'd see a second sun, Carter says. There may also be no night during that timeframe."

http://www.huffingtonpost.com/2011/0..._n_811864.html

Chronos

Wow, this is total nonsense guys. Get over it.

Drakkith

What is total nonsense?

phyzguy

I agree that it's nonsense.

The 'second sun' stuff is simply wrong. Type-II supernovae typically have absolute magnitudes of around -17 to -20. At Betelgeuse' distance of 200 pc, this give an apparent magnitude of -10.5 to -13.5. The full moon is about magnitude -13, and the sun is magnitude -27. So this means at best it will be about as bright as the full moon - impressive, but nowhere near as bright as the sun.

Also, this paragraph,

"In fact, a neutrino shower could be beneficial to Earth. According to Carter this "star stuff" makes up the universe. "It literally makes things like gold, silver - all the heavy elements - even things like uranium....a star like Betelgeuse is instantly forming for us all sorts of heavy elements and atoms that our own Earth and our own bodies have from long past supernovi," said Carter.

is ridiculous. First, in what way is the neutrino shower beneficial? At best, it has no impact on us. If the neutrino flux were high enough to be noticeable(it won't be), it would be a type of high-energy radiation, and it's impact on us would be bad. Second, in what way is it to our advantage that Betelgeuse is making gold, silver, etc. that is 600 light-years away? If we want to mine metals in space, there are huge stores here in our solar system that are vastly closer than trotting out 600 ly to Betelgeuse to mine a fresh, radioactive supernova.

Drakkith

The article was updated saying the neutrino flux wouldn't be beneficial, but the creation of heavy elements would. Which is still kind of bogus...