Betelgeuse! Betelgeuse! Betel-- BOOM!

[sanman]

A story on Fox says that Betelgeuse may be about to go supernova:

http://www.foxnews.com/story/0,2933,525695,00.html

Is the supernova process that quick, that it can be identified so quickly?
Wow, and Betelgeuse is supposed to be a rather prominent star which has been known to us for a long time.
Strange to know that it's now about to leave us.

[hhEb09'1]

I think this has been expected, this is just another data point making it more likely. It's variability has been observed before (actually, the article says it hasn't been variable over the past decade, just its size has shrunk)

[Buttercup]

Love the title!

[KaiYeves]

Yes, great title.

Say his name three times and he blows up!

[matthewota]

I used to work next to the telescope that is being used in that project. the telescope system is the most unlikely telescope I have ever seen. It consists of three box trailers that have retractible ends. More can be seen about this unusual telescope here.

The original Berkely news release is here.

Nice to see some viable science being accomplished with this equipment.

If Betelgeuse explodes it is near enough to be seen in broad daylight, a supernova that will exceed the one that created the Crab nebula.

[tdvance]

Would it be the first time, since say the ancient Egyptians and star charts that were more accurate and complete than a bear drawn on a cave wall, that a constellation has lost its form? I know Bootes has a slightly different shape than 3000 years ago because Aldebaran moves so fast, but it was just as much a herdsman then as now (or just as much not, if you can't see the herdsman in it). But this one would cost Orion an arm!

[Ampatent]

So if it were to occur is there going to be a gradual increase in light or an immediate shock of luminosity?

[George]

So if it were to occur is there going to be a gradual increase in light or an immediate shock of luminosity?

It will become increasingly brighter over a period of a few weeks or more, then it will slowly dim over a period of many months. [More here. ] The outer envelope it spews prior to the explosion apparently has an affect on what we see.

At 640 lightyears, and it may be slightly closer, a light echo [if one actually happened] off the envelope will appear to us to be about the size of the Moon in only 2.5 years, though not visibly bright by then.

[Tog]

It will become increasingly brighter over a period of a few weeks or more, then it will slowly dim over a period of many months. [More here. ] The outer envelope it spews prior to the explosion apparently has an affect on what we see.

At 640 lightyears, and it may be slightly closer, a light echo [if one actually happened] off the envelope will appear to us to be about the size of the Moon in only 2.5 years, though not visibly bright by then.

Any chance the remaining "nebula" would be visible naked eye? If so, any idea for how long?

[George]

Any chance the remaining "nebula" would be visible naked eye? If so, any idea for how long?

Just wild guessing, but I would say yes if, by luck, a strong light echo takes place after about 5 months so that the apparent angular size is greater than the resolution of our eyes (1 arcminute). After 5 months, the size for the light echo would only be about 2 arcminutes, which is still very small.

The ultraviolet flash will rise to peak in about 12 hours or so and fade within 2 days. Roughly, Betelgeuse could get as bright as Venus, and turn extremely blue, as most of the energy is released in the UV.

Is this a spike within the spectrum, or more of a BB distribution?

Still it should exceed the brightness of the full moon by one or two magnitudes, and this as a point source!! This will mean it will actually be dangerous to look at, the surface brightness will be close to that of the sun.

Yes, it will be very bright. Assuming the brightness reaches about -17, it will have an apparent surface brightness about 1/6th that of the Sun. [Sun has about 800 sq. arcminutes but is about 5000x the brightness.] But even this is still very bright.

[Don Alexander]

So if it were to occur is there going to be a gradual increase in light or an immediate shock of luminosity?

Well, there have been GALEX observations where an early ultraviolet flash was discovered seredipituously from exploding red supergiants like this one, and the same phenomenon has been seen in more detail in the high-energy transient associated SNe 2006aj (XRF 060218) and 2008D (XRO 080109).

What can probably be expected is an initial very powerful X-ray outburst lasting some thousands of seconds which may have significant effects on the atmosphere, such as producing aurora, heating it and endangering satellites and their electronics. (Though this is not comparable to a nearby GRB and should not have any long-term deletirious effects).

The ultraviolet flash will rise to peak in about 12 hours or so and fade within 2 days. Roughly, Betelgeuse could get as bright as Venus, and turn extremely blue, as most of the energy is released in the UV.

Then, as mentioned above, the magnitude will rise within some weeks to a radioactive-decay driven peak. I don't think anyone can say what kind of SN (apart from Type II, d'oh) Betelgeuze will turn into. If there is interaction with the circumstellar medium (it's own ejected gas layers), it could become quite fiercely bright.

AFAIK, the brightest SN is recorded history was SN 1006, which was supposed to have reached the brightness of the quarter moon, so roughly mag -10.5. Seeing this was very probably a Type Ia, it should have been roughly M = -19.5, and it's about 2.2 kpc away. Betelgeuze is more than TEN times nearer, but may only reach M = -17. Still it should exceed the brightness of the full moon by one or two magnitudes, and this as a point source!! This will mean it will actually be dangerous to look at, the surface brightness will be close to that of the sun.

If it occurs during northern winter, it will be visible most of the night. Which means that for at least a few months, astronomy will turn into a study of SN Betelgeuze, and almost nothing else, because it will create terrible light pollution. If it occurs in summer, pity, it will not be so easy to study, but will be clearly seen during daylight.

I'm not sure about either the possible dust echo or the SN remnant. I'm pretty sure they will not be visible to the naked eye.

[AndrewJ]

Would it be the first time...that a constellation has lost its form? I know Bootes has a slightly different shape than 3000 years ago because Aldebaran moves so fast [my bold]

Arcturus?

[novaderrik]

when this star blows up, how many new age weirdos are gonna come crawling out of the woodwork to say that it's a sign of some sort of impending apocalypse or something?
will it be like the comet back in '87 where a few people bought Nikes and drank purple Kool Aid laced with poison, or will it be more dramatic than that?

[eburacum45]

The outer layers of Betelgeuse are very thin and very very variable in form. See this page of simulations
http://www.astro.uu.se/~bf/movie/dst...n26/movie.html

and the outer layers may be structured in different layers with irregular 'holes' in them.
http://www.mrao.cam.ac.uk/telescopes/coast/betel.html

With all this variation I would not be surprised to learn that Betelgeuse regularly shrinks and expands over a period of decades, and that what we are seeing is normal behaviour for this very variable star.

[agingjb]

The Crab nebula is around mag 8.4, Betelgeuse is ten times nearer, so a comparable remnant (if any) might be visible (ish) at an optimistic 3 to 4 at some time?

[trinitree88]

For rookies....There's a good NASA tutorial here on late phase evolution:http://rst.gsfc.nasa.gov/Sect20/A7.html
It is surprising to find considerable spectral evidence for iron since at least 2000 see:http://www.iop.org/EJ/article/0004-6...2704.text.html. Why? Most stellar models I see infer slow mixing of isotopic abindances from the stellar interior, with a sole exception over the last few decades. (I expect some more knowledgeable astrophysicists to set me straight here). Betelgeuse has shown UV spectra indicating iron for years now. Only a few of the supernova theorists allow models wherein the iron in the core can accumulate for ~ 10 years before a core collapse type 2 supernova occurs. We appear to be on that upper limit of the temporal models. I agree.
Here's a chance for Antoniseb to win another dinner. I already bet that Alnitak would go in two years, and lost. I betcha a Thai dinner that Betelgeuse will go supernova in less than two years, June 12 (a very special person's birthday) 2011. I betcha, I betcha, I boom-ya....pete

[Hornblower]

For rookies....There's a good NASA tutorial here on late phase evolution:http://rst.gsfc.nasa.gov/Sect20/A7.html
It is surprising to find considerable spectral evidence for iron since at least 2000 see:http://www.iop.org/EJ/article/0004-6...2704.text.html. Why? Most stellar models I see infer slow mixing of isotopic abindances from the stellar interior, with a sole exception over the last few decades. (I expect some more knowledgeable astrophysicists to set me straight here). Betelgeuse has shown UV spectra indicating iron for years now. Only a few of the supernova theorists allow models wherein the iron in the core can accumulate for ~ 10 years before a core collapse type 2 supernova occurs. We appear to be on that upper limit of the temporal models. I agree.
Here's a chance for Antoniseb to win another dinner. I already bet that Alnitak would go in two years, and lost. I betcha a Thai dinner that Betelgeuse will go supernova in less than two years, June 12 (a very special person's birthday) 2011. I betcha, I betcha, I boom-ya....pete

My educated guess is that the iron in Betelgeuse's chromosphere was present in the cloud of gas and dust from which the star formed, as a result of previous generations of supernovae. Betelgeuse is a very recent object on the cosmic time scale.

[George]

Here's a chance for Antoniseb to win another dinner. I already bet that Alnitak would go in two years, and lost.

Twas a hot fudge sundae, and for two winners.

[trinitree88]

Twas a hot fudge sundae, and for two winners.

George. OK, I'm "fessin "up...yep I owes ya one too! ....at the next heliochromology conference. A first rate theory predicts & pays up when it fails. pete

[George]

George. OK, I'm "fessin "up...yep I owes ya one too! ....at the next heliochromolgy conference. A first rate theory predicts & pays up when it fails. pete

Double or nuttin'??

[antoniseb]

I betcha a Thai dinner that Betelgeuse will go supernova in less than two years, June 12 (a very special person's birthday) 2011. I betcha, I betcha, I boom-ya....pete

Let me be *very* clear that I do not make this kind of bet with just anyone on any topic. However, in hopes that I will lose this bet, I accept.

Let me also say that I do not regard the mere shrinking of this puffy envelope as an obvious indicator. I (sadly) think I will win this bet.

[trinitree88]

Let me be *very* clear that I do not make this kind of bet with just anyone on any topic. However, in hopes that I will lose this bet, I accept.

Let me also say that I do not regard the mere shrinking of this puffy envelope as an obvious indicator. I (sadly) think I will win this bet.

Ha! You're on. I can feel the neutrinos streaming through me already...lol pete

[Gigabyte]

Here's a chance for Antoniseb to win another dinner. I already bet that Alnitak would go in two years, and lost. I betcha a Thai dinner that Betelgeuse will go supernova in less than two years, June 12 (a very special person's birthday) 2011. I betcha, I betcha, I boom-ya....pete

Let me be *very* clear that I do not make this kind of bet with just anyone on any topic. However, in hopes that I will lose this bet, I accept.

Let me also say that I do not regard the mere shrinking of this puffy envelope as an obvious indicator. I (sadly) think I will win this bet.

Can I get in on this action?

[antoniseb]

Can I get in on this action?

Maybe with Trinitree but not with me.

[trinitree88]

Can I get in on this action?

Robinson.OK. You're on. .....two on the line. I'm in a gambling mood. pete

[Don Alexander]

The Crab nebula is around mag 8.4, Betelgeuse is ten times nearer, so a comparable remnant (if any) might be visible (ish) at an optimistic 3 to 4 at some time?

Well, I strongly assume that that's the integrated magnitude of the whole nebula. The Andromeda Galaxy also is third magnitude integrated, but it's nowhere as visible as typical third magnitude stars.

Is this a spike within the spectrum, or more of a BB distribution?

Blackbody, peaking in the far ultraviolet.

...depending on how far away this star actually is. Because it's a variable, it is a bit of a difficult one to pin down. Celestia, based on the Hipparchos readings, places it only 427 light years away. Wikipedia places it about 600 ly. If its going to blow, it might be less painful to observe if it is slightly further away (too close and you will need special glasses to look at it).

It seems the old Hipparcos distance of 427 ly is in error. Last year, a new measurement combining Hipparcos and VLBI came out, placing it at about 660 ly.

[George]

Blackbody, peaking in the far ultraviolet.

If it does come close to a blackbody distribution, then it will only look slightly blue. You will need the temperature to be about 10 million degrees or so in order to get enough of the blues outweighing the other colors in order to see a blue the would match something like the blue sky overhead. The Sun's core, for instance, would look very blue if we could take a quick look at it and at a greatly reduced level tolerable for our eyes.

[Don Alexander]

If it does come close to a blackbody distribution, then it will only look slightly blue. You will need the temperature to be about 10 million degrees or so in order to get enough of the blues outweighing the other colors in order to see a blue the would match something like the blue sky overhead. The Sun's core, for instance, would look very blue if we could take a quick look at it and at a greatly reduced level tolerable for our eyes.

Well, I wasn't trying to imply it would be a pure blue, sorry. More like the bluish white seen in early B stars (like Rigel) and O stars.

Though as yet it is not clear what the actual evolution of the X-ray eruption and this "shock breakut" peak are. Possibly, the are one and the same flash which rapidly cools and expands. XRF 060218/SN 2006aj, where the UV flash was observed in detail, had early X-ray emission that was mostly swamped by a non-thermal low-luminosity/energy gamma-ray burst (though a rising thermal component is visible in the second thousand seconds of the explosion), whereas XRO 080109 (O standing for Outburst, as it very probably is not due to the same processes that produce GRBs)/SN 2008D lay behind a significant amount of host galaxy extinction, which strongly damped the UV flash, so there are only sparse data.

@Jerry: Whoops, it was 640, not 660 ly. I got this from Jim Kaler's page, and ADS led my to the paper. Alas, it is NOT on astro-ph (silly, silly - the paper we are actually discussing in this thread also isn't), so I can only give abstracts now:

The distance to the M supergiant Betelgeuse is poorly known, with the Hipparcos parallax having a significant uncertainty. For detailed numerical studies of M supergiant atmospheres and winds, accurate distances are a prerequisite to obtaining reliable estimates for many stellar parameters. New high spatial resolution, multiwavelength, NRAO Very Large Array (VLA) radio positions of Betelgeuse have been obtained and then combined with Hipparcos Catalogue Intermediate Astrometric Data to derive new astrometric solutions. These new solutions indicate a smaller parallax, and hence greater distance (197 +/- 45 pc), than that given in the original Hipparcos Catalogue (131 +/- 30 pc) and in the revised Hipparcos reduction. They also confirm smaller proper motions in both right ascension and declination, as found by previous radio observations. We examine the consequences of the revised astrometric solution on Betelgeuse's interaction with its local environment, on its stellar properties, and its kinematics. We find that the most likely star-formation scenario for Betelgeuse is that it is a runaway star from the Ori OB1 association and was originally a member of a high-mass multiple system within Ori OB1a.

The diameter of Betelgeuse (α Orionis) has been measured at a wavelength of 11.15 μm using the Infrared Spatial Interferometer over the past 15 years. During this 1993-2009 time period the star's size has decreased systematically by 15%.

Hm, the latter doesn't contain a lot of info...

[George]

Well, I wasn't trying to imply it would be a pure blue, sorry. More like the bluish white seen in early B stars (like Rigel) and O stars.

Ok, I was thinking that perhaps you might be refering to more of a spike in the spectrum due to elemental decay of specific elements perhaps, and not a bb distribution.

Though as yet it is not clear what the actual evolution of the X-ray eruption and this "shock breakut" peak are. Possibly, the are one and the same flash which rapidly cools and expands. XRF 060218/SN 2006aj, where the UV flash was observed in detail, had early X-ray emission that was mostly swamped by a non-thermal low-luminosity/energy gamma-ray burst (though a rising thermal component is visible in the second thousand seconds of the explosion), whereas XRO 080109 (O standing for Outburst, as it very probably is not due to the same processes that produce GRBs)/SN 2008D lay behind a significant amount of host galaxy extinction, which strongly damped the UV flash, so there are only sparse data.

Are there SEDs of any of these? I would assume non-thermal emissions would not be that close to a blackbody.

[Jerry]

It seems the old Hipparcos distance of 427 ly is in error. Last year, a new measurement combining Hipparcos and VLBI came out, placing it at about 660 ly.

This almost floors me. I was slapped about the board for stating there were significant errors in the Hipparcos distance scales that were broadly defended by the PIs for ~ a decade. 30% is not a big error in astronomical terms, but it is kinda bad for an object this close.