The star Betelgeuse going supernova soon?


by Glennage
Tags: betelgeuse, star, supernova
Borek
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#19
May24-10, 10:20 AM
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Quote Quote by Glennage View Post
So why wouldn't betelgeuse send out a GRB?
Note that GRB is narrow - that means it is emitted in one direction. It doesn't have to shine on everything.
Mu naught
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#20
May24-10, 10:32 AM
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It could go tomorrow or in a million years. I wouldn't hold your breath.
mgb_phys
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#21
May24-10, 10:48 AM
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Quote Quote by Borek View Post
Just note that neutrinos are earlier not because they travel faster, but because they are produced at the earlier stage of the explosion.
They also get out of the surrounding envelope faster because they don't get scattered.

Betelgeuse isn't massive enough to form a GRB (hopefully)
However it's disappearance will have the effect of making my PhD thesis (IR interferometer imaging of Betelguese) even more irrelevant than it currently is.
Mu naught
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#22
May24-10, 11:22 AM
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Quote Quote by mgb_phys View Post
They also get out of the surrounding envelope faster because they don't get scattered.

Betelgeuse isn't massive enough to form a GRB (hopefully)
However it's disappearance will have the effect of making my PhD thesis (IR interferometer imaging of Betelguese) even more irrelevant than it currently is.
Lol!
Philosophaie
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#23
May29-10, 06:31 PM
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I hope it waits till next fall or we may miss the spectacular show like the Crab Nebula must have been barring an extra-large x-ray radiation event. I hope we see it happen then are safely behind the sun when the Gamma ray burst occurs.
Borek
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#24
May30-10, 03:51 AM
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Quote Quote by Philosophaie View Post
I hope it waits till next fall or we may miss the spectacular show like the Crab Nebula must have been barring an extra-large x-ray radiation event. I hope we see it happen then are safely behind the sun when the Gamma ray burst occurs.
It ain't gonna happen. The only situation Sun can screen us is when the object is exactly in the Earth orbit plane - Betelgeuse is above. And even then we can be behind Sun only for about 12 hours - that is, Sun lies between us and any other distant object for only about 0.15% of the time. We would need a lot of luck.
Unix Ronin
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#25
May30-10, 05:35 PM
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I've been looking a little at this myself lately. The original source, unfortunately, is not verifiable. However, it's basically not inconsistent with existing observations of Betelgeuse, which indicate that after a long period of fluctuation in size with a period on the order of several years, it has been shrinking continuously (and at an increasing rate) since 1993. If this does reflect a permanent change in the internal state of the star and Betelgeuse has entered its final collapse, we would expect it to become progressively more non-spherical as it collapses. I imagine I don't need to point out that the brightness estimates in the initial article are WAY off, though.

The original post uses SN1054 as a reference. Let's do that. And let's also look at SN1006, although SN1006 was probably a Type 1a supernova. SN1054, at a distance estimated at 6300LY, is estimated based on accounts written at the time to have reached apparent magnitude -6. SN1006, the brightest extra-solar stellar event ever observed and recorded by humans, reached absolute magnitude -7.5 from a distance estimated at 7200LY. Measurements of Betelgeuse's distance vary from 495LY to about 620LY, with the "best compromise" estimates considered to lie between 530LY and 570LY.

To start with, if we assume Betelgeuse would be like a SN1054 event, we can predict that simply by virtue of being between 11 and 12 times closer, a Type II supernova of Betelgeuse would appear somewhere in the region of 130 to 140 times brighter than SN1054 merely by virtue of being closer. This would mean an apparent magnitude somewhere around -12, making it a little less than half as bright as the full moon (magnitude -12.92).

This, however, assumes that Betelgeuse is just like the progenitor star of SN1054, which it is not. We believe that SN1054's progenitor star was between 9 and 11 solar masses. This is about half the mass of Betelgeuse, estimated at 20 solar masses. We can therefore expect Betelgeuse's supernova to be a considerably more energetic event than SN1054, but we don't know by how much. So let's also compare to SN1006, which was a full 1.5 magnitudes brighter than SN1054 despite being almost 1000LY further away. We can readily calculate that SN1006 had to have an absolute luminosity on the order of 5.2 times that of SN1054. This is a little under two magnitudes.

So, if we assume that a Type II supernova of Betelgeuse would be at least as luminous as SN1054 (a not unreasonable assumption), but no more luminous than SN1006, we can ballpark its probable apparent magnitude at somewhere in the range of -12 to -14, or, in other words, from roughly half to roughly twice the maximum brightness of the full moon. (Remember, though, to visual observation it will be a point source. It will be piercingly brilliant.) But there is no way it's going to be 12 to 13 magnitudes (absolute) brighter than SN1006, which is what it would take to rival the Sun.

So, as bright as the full moon? Very likely. As bright as the sun? Not a chance, unless something far more catastrophic happens than our understanding of stellar evolution would currently lead us to expect.
Unix Ronin
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#26
May30-10, 05:37 PM
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Quote Quote by Philosophaie View Post
I hope it waits till next fall or we may miss the spectacular show like the Crab Nebula must have been barring an extra-large x-ray radiation event. I hope we see it happen then are safely behind the sun when the Gamma ray burst occurs.
On the basis of current understanging, there is no known danger to Earth of a GRB from Betelgeuse. We aren't anywhere near to close enough to being in line with Betelgeuse's poles.
rathat
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#27
Jun1-10, 04:06 PM
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I saw something that said it could happen within a few weeks?


source
http://unixronin.livejournal.com/763082.html

can someone verify this?
stevenb
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#28
Jun1-10, 04:13 PM
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Quote Quote by rathat View Post
I saw something that said it could happen within a few weeks?


can someone verify this?
Yes, I can verify whether or not this is true, but I'm a little busy right now. I'll get back to you in two months.
Mu naught
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#29
Jun1-10, 06:33 PM
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I wouldn't bet on it but it would certainly be exciting. I'll be disappointed to see poor Orion's shoulder mangled when/if I live to see Betelgeuse go.
rathat
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#30
Jun1-10, 10:36 PM
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I NEED to find out if this is true.
stevenb
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#31
Jun1-10, 11:33 PM
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Quote Quote by rathat View Post
I NEED to find out if this is true.
Seriously though, all you need to do is wait and see. In a few weeks you'll know. Before that, nobody can possibly know for sure. I'd love to live to see it, but I don't think the odds are in my favor.

Out of curiosity, why the NEED to find out?
Antiphon
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#32
Jun2-10, 12:56 AM
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I think it will be seen to go nova on December 21, 2012. It will form a rotating black hole with a pulsating torch beam and incinerate the earth.

Perhaps you should consider selling me your house at a steep discount. What with the world ending and all it would be the prudent move.
Unix Ronin
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#33
Jun2-10, 07:39 AM
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Quote Quote by rathat View Post
I saw something that said it could happen within a few weeks?

source
http://unixronin.livejournal.com/763082.html

can someone verify this?
Well, it still technically COULD. But there's now at least reasonably reliable refutation (alliteration über alles!) of the original, dubious and unverified, report on which all the speculation was based, via the bad Astronomy Blog on discovermagazine.com. As was highly probable right from the start, it's just an unverified rumor based on a misunderstanding of already known data. There is no dramatic new observation.

Astronomers have been saying for years that Betelgeuse could easily go at any time within the next thousand years or so, but based on that article, there's no actual direct evidence that it's fixing to do so Right Now. Which is kind of a shame; in addition to being a truly spectacular show, it would have given us huge amounts of data on how a Type II supernova actually happens.

But ... no BOOM! today. Nor probably tomorrow. Maybe next year, or two or three hundred years from now.

"Where is my Betelgeuse-shattering KABOOM? There was supposed to be a Betelgeuse-shattering KABOOM!"
brother time
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#34
Jun3-10, 11:32 AM
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Betelgeuse is towards the end of it's life. However the big Kaboom could be in several thousand years as it usually is with stars. It would be cool to watch but unlikely for us to see it. :(
BT
Chewy0087
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#35
Jun3-10, 05:57 PM
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The challenge now becomes to try to keep this thread alive until it actually does go supernova! (as in, we see it go supernova).
soulfien
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#36
Jul10-11, 04:20 PM
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Quote Quote by Glennage View Post
So the really lucky folks (for whom Betelgeuse is only visible at night) will get 24 hour days, everybody else will get at least some time with two suns in the sky. The extra hour of light from daylight savings time won't burn the crops, but this might. Probably, all we'll get is visible light (not gamma rays or X-rays), so it shouldn't be an ELE. It's sure gonna freak everyone out, though.....
Daylight Savings does nothing to add or remove sunlight from crops. Simply offsetting our house clocks doesn't alter the course of the sun.


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