http://backreaction.blogspot.com/2009/06/shrinking-betelgeuse.html

 

Giant stars have a short lifetime. Consume their fusible elements rapidly.

When there is nothing more to fuse, they start cooling and shrinking, then collapse and blow.

 

Interesting to study the shoulder star Betelgeuse (alpha Orionis) with that possibility in mind.

It is close enough that instruments can actually resolve it and can measure the diameter by a couple of different methods.

 

 

Diameter measurements by different teams over the course of fifteen years or so show a downtrend.

This could be part of a cycle--and destined to reverse itself. Or it might continue shrinking.

At the moment it is just speculation. Some people speculate that the star has already gone supernova

and we will find out in 600 years or less (since it is some 600 lightyears away.)

 

Others take a more wait-and-see attitude: "let's watch for another 15 years and see what it does."

 

http://www.berkeley.edu/news/media/releases/2009/06/09_betelim.shtml

 

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BTW this is not to worry about. The rotation axis of the star is not pointed in our direction.

 

Here's some additional comment, by John Baez:

http://math.ucr.edu/home/baez/week276.html

Edited June 22, 200916 yr by Martin

If it goes supernova, that would be quite a show, I guess. I almost would wish that it blows up tomorrow.

If it goes supernova, that would be quite a show, I guess. I almost would wish that it blows up tomorrow.

 

if it blew up tomorrow you'll need to wait a few centuries before seeing it.

 

what you really want is for it to have blown up a few centuries ago so we can see it now.

Umm, yeah.

That's what I meant, obviously.

If it blew up today, we would have to wait until the year 2650 before we saw it over Earth. Just wondering, what is the amount of radiation from this supernova that would hit us?

Edited July 3, 200916 yr by Reaper

assuming it is standard for a super nova, the total energy recieved will be approximately equal to 10 minutes of noon sunshine.

 

however, the even will last much longer than 10 minutes so that'll be spread over a few weeks. this is counting energy carried by particle radiation as well which will probably take a few centuries more to hit.

You never know, maybe it did blow up centuries ago and we'll see it tomorrow.