Kevin's Watch

Betelgeuse, Red Supergiant In Constellation Orion, Has Shrunk By 15 Percent In 15 Years

How awesome would it be to see a supernova in our lifetime?

www.sciencenews.org/view/generic/id/445 ... se_shrinks
www.plastic.com/article.html;sid=09/06/ ... 733;cmt=28

Syl wrote:Betelgeuse, Red Supergiant In Constellation Orion, Has Shrunk By 15 Percent In 15 Years

How awesome would it be to see a supernova in our lifetime?

It would be way awesome.

Of course, if it was anywhere nearby, we'd be screwed.

Haven't looked at any of the links, but I think Betelgeuse is at a safe remove of 500 LY or so.

Currently, it is believed that Betelgeuse is fusing helium into carbon and oxygen at its core. Given its vast mass (12 to 17 times the sun), it is possible (likely) that it could turn supernova. However, the star's rotational axis is not lined up with our solar system so it is unlikely that if Betelgeuse were to explode we would be hit with a gamma ray burst. Further, the star is around 640 light years away so life is safe.

As for the mass loss - Betelgeuse is a red supergiant and is losing a lot of its mass to a stellar wind. Note that the star has been observed to pulsate, which may suggest the mass loss measure. But I agree with the article; the frequent interferometer observations are unlikely to concur. Betelgeuse has been observed to have a bumpy surface, so as it rotates we may have varying size measures (read: size artefacts).

Importantly, Betelgeuse has large amounts of gas and dust surrounding it, so this may impair measures.

This is good news for the EndoftheWorlders. When 2012 doesn't pan out, they'll have this as their ace-in-the-hole for the next 9-999 thousand years.

I wonder what Nostradamus has to say on the matter?

The end of the world in 2012 or the new age will never occur And Nostradamus is a git.

Loremaster wrote:The end of the world in 2012 or the new age will never occur And Nostradamus is a git.

Ya think?!?



The worst aspect of the EndoftheWorlders IMO, is not that they predict the end of the World, but that they're gleefully looking forward to it.

Sounds like Ford Prefect's family is f*cked.

Demondim-spawn wrote:The worst aspect of the EndoftheWorlders IMO, is not that they predict the end of the World, but that they're gleefully looking forward to it.

Well said.

Cail wrote:Sounds like Ford Prefect's family is f*cked.

Yeah. Even their towels won't do them much good in the event their star goes supernova.

If Betelgeuse went supernova, it would probably outshine our Moon at night for several months and might well be visible during daylight hours,

How awesome would that be?!

dlbpharmd wrote:

If Betelgeuse went supernova, it would probably outshine our Moon at night for several months and might well be visible during daylight hours,

How awesome would that be?!

[CLIFFCLAVINMOMENT] If it outshone the Moon at night then it's guaranteed to be visible during daylight hours, just as the Moon is.

Though it would remain a point source of light for 10s if not hundreds of years before it spread out far enough to be the apparent SIZE of the moon (1/2 degree of arc).

Also: Remember, that at Betelguese's distance, if we see it go supernova tomorrow, it means it happened 640 years ago in 1369 CE, and if it goes supernova tomorrow, we won't know about it until 2649 CE. [/CLAVIN]

dlbpharmd wrote:

If Betelgeuse went supernova, it would probably outshine our Moon at night for several months and might well be visible during daylight hours,

How awesome would that be?!

Very.

My camera will see a lot of action if it ever happens.

(And yes, Nostrilmucus-whats-his-name is totally a git.)

Awesome indeed!

Loremaster: I never understood why gamma-ray bursts occur parallel to the rotational axis. When a rotating spherical object disintegrates everything else leaves it along vectors pependicular to the rotational axis doesn't it?

Gamma Ray Bursts are still largely mysterious. In that we are not sure why these bursts occur. However, two theories currently exist. There is burst originating when two stars collide. The second type of burst occurs when a black hole forms within a star. Both produce an intense burst of energy parallel to the rotational axis of the star.

As it happens, Betelgeuse is massive enough for a black hole to form in its core. It is theorised that this will result in a gamma ray burst. Why will it be parallel as opposed to perpendicular. Because an accretion disk will form around the black hole as well as a relativistic jet. Twisting magnetic fields in the accretion disk directs the flow of matter outward. As the jet hits the outer shells of the expanding star, gamma rays are emitted. You will not see gamma rays perpendicular to the star, and instead there will be x-rays emmitted by matter as it falls into the black hole.

Thanks Loremaster. Relativistic jet. Yeah, that's easy for you to say I had a feeling that Newtonian mechanics wouldn't suffice to explain the diretion of the gamma ray burst, and alas, that's as far as my current understanding of physics go. But thanks for trying

Prebe wrote:Thanks Loremaster. Relativistic jet. Yeah, that's easy for you to say I had a feeling that Newtonian mechanics wouldn't suffice to explain the diretion of the gamma ray burst, and alas, that's as far as my current understanding of physics go. But thanks for trying

Yeah, 2 semesters of college physics didn't prepare me for that answer either.

Demondim-spawn wrote:...at Betelguese's distance, if we see it go supernova tomorrow, it means it happened 640 years ago in 1369 CE, and if it goes supernova tomorrow, we won't know about it until 2649 CE.

Yeah, that's what I was thinking about...is the mass loss and whatever based on what it looks like to us right now?

--A

Avatar wrote:Yeah, that's what I was thinking about...is the mass loss and whatever based on what it looks like to us right now?

--A

Technically all red supergiants will lose mass due to a strong stellar wind. That has not been observed, but it is likely since our own star has one. Because of optical interferometry, astronomers have measured the star's disc as opposed to seeing a point. Based on these observations, they know that the disc pulsates, and I guess they also have seen that it is currently smaller.

Loremaster wrote:

Avatar wrote:Yeah, that's what I was thinking about...is the mass loss and whatever based on what it looks like to us right now?

Technically all red supergiants will lose mass due to a strong stellar wind. That has not been observed, but it is likely since our own star has one. Because of optical interferometry, astronomers have measured the star's disc as opposed to seeing a point. Based on these observations, they know that the disc pulsates, and I guess they also have seen that it is currently smaller.

Bear in mind that we're watching 640-year-old newscasts.

Is it possible to predict the Second World War by studying newsreels of (say) Neville Chamberlain triumphantly waving a piece of paper? Probably not.

Studying the detailed changes in Betelguese over the span of 15 years is quite an achievement, but that's less than a blink in the lifetime of a star, and that particular 15 year long blink happened 43 blinks ago.