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sanman
2009-Jun-10, 09:33 PM
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
2009-Jun-10, 09:46 PM
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
2009-Jun-10, 10:13 PM
:lol: Love the title!

KaiYeves
2009-Jun-10, 10:31 PM
Yes, great title.

Say his name three times and he blows up!

matthewota
2009-Jun-10, 10:41 PM
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 (http://isi.ssl.berkeley.edu/).

The original Berkely news release is here. (http://www.berkeley.edu/news/media/releases/2009/06/09_betelim.shtml)

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
2009-Jun-11, 01:26 AM
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
2009-Jun-11, 02:07 AM
So if it were to occur is there going to be a gradual increase in light or an immediate shock of luminosity?

George
2009-Jun-11, 04:29 AM
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 (http://astronomy.swin.edu.au/cms/astro/cosmos/T/Type+II+Supernova+Light+Curves). ] 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
2009-Jun-11, 05:43 AM
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 (http://astronomy.swin.edu.au/cms/astro/cosmos/T/Type+II+Supernova+Light+Curves). ] 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?

novaderrik
2009-Jun-11, 06:13 AM
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
2009-Jun-11, 06:30 AM
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/dst35gm04n26/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.

Don Alexander
2009-Jun-11, 08:05 AM
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.

agingjb
2009-Jun-11, 08:32 AM
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
2009-Jun-11, 11:46 AM
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/0004-637X/558/2/815/52704.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
2009-Jun-11, 01:01 PM
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/0004-637X/558/2/815/52704.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
2009-Jun-11, 03:51 PM
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.

George
2009-Jun-11, 04:00 PM
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 (http://www.bautforum.com/universe-today-story-comments/40447-strange-nebula-around-eta-carinae.html#post730952). :whistle: :)

rommel543
2009-Jun-11, 04:06 PM
So when the arm or Orion goes pop, will there be a worry here? That is, is there any concern of increase cosmic radiation knocking out satellites, increase in gamma radiation affecting the planet, etc?

pumpkinpie
2009-Jun-11, 04:22 PM
Reading through things carefully.....
The original Berkeley release that matthewota posted, which was listed as the source in the Fox News article sanman posted in the OP, does not say that the shrinking of Betelgeuse indicates an impending supernova. Neither do any quotes from the Berkeley researcher.

It still is an interesting story, but the conclusion in the new story should necessarily be believed unless we hear from the Berkeley group or other scientists that there is a definite connection.

ETA: Even Tuesday's Universe Today (http://www.universetoday.com/2009/06/09/the-case-of-the-incredible-shrinking-star/) article said nothing about the possibility of a supernova.

trinitree88
2009-Jun-11, 04:24 PM
Twas a hot fudge sundae, and for two winners (http://www.bautforum.com/universe-today-story-comments/40447-strange-nebula-around-eta-carinae.html#post730952). :whistle: :)

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.:shifty::lol: pete

sohh_fly
2009-Jun-11, 04:30 PM
Is the rotation axis pointed in our direction?
Also any idea of how big a shell will be created,enough to reach earth?

antoniseb
2009-Jun-11, 05:36 PM
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.

George
2009-Jun-11, 05:51 PM
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.:shifty::lol: pete
:) Double or nuttin'??

George
2009-Jun-11, 05:54 PM
Reading through things carefully.....
The original Berkeley release that matthewota posted, which was listed as the source in the Fox News article sanman posted in the OP, does not say that the shrinking of Betelgeuse indicates an impending supernova. Neither do any quotes from the Berkeley researcher. True, but they indicate that there is a possibility here for a supernova...



It's possible we're observing the beginning of Betelgeuse's final collapse now.

If so, the star, which is 600 light-years away, will already have exploded — and we'll soon be in for a spectacular, and perfectly safe, interstellar fireworks show.

Argos
2009-Jun-11, 06:08 PM
Well, case it has exploded, the fireworks display will be enjoyed by the people of the 26th century.

eburacum45
2009-Jun-11, 07:31 PM
Unless it exploded five hundred years ago.

...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).

pumpkinpie
2009-Jun-11, 08:50 PM
True, but they indicate that there is a possibility here for a supernova...

From which article is that? I only looked at their official press release. I did a search for "berkeley begelgeuse supernova" and the only results I got were pointing back to the Fox News article.
Thanks.

trinitree88
2009-Jun-11, 11:20 PM
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:lol: pete

trinitree88
2009-Jun-11, 11:22 PM
:) Double or nuttin'??

Ha,too! You're on. Double or nuttin. Definitely a nut on this end.:shifty::lol: pete

George
2009-Jun-12, 12:54 AM
From which article is that? I only looked at their official press release. I did a search for "berkeley begelgeuse supernova" and the only results I got were pointing back to the Fox News article.
Thanks.
I quoted directly from the Berkely release (http://www.berkeley.edu/news/media/releases/2009/06/09_betelim.shtml). [Oops it was the original Fox release]


Ha,too! You're on. Double or nuttin. Definitely a nut on this end.:shifty::lol: pete It'll be a blast if you win, so good luck. :)

Jens
2009-Jun-12, 01:38 AM
Well, case it has exploded, the fireworks display will be enjoyed by the people of the 26th century.

It's an interesting point, because it illustrates how confusing it can be when people say, "it's about to blow up." What they really mean is probably, "it blew up at a time when it's about to appear to us that it's blown up," but it can be confusing because people aren't necessarily talking about the same thing.

pumpkinpie
2009-Jun-12, 01:59 AM
I quoted directly from the Berkely release (http://www.berkeley.edu/news/media/releases/2009/06/09_betelim.shtml).


Sorry to be picky, but I just don't see that statement in that article. (Are my eyes deceiving me?)

I am not doubting that you read it. I just want to be sure to have the facts straight that they did in fact link the shrinking to the possibility of a supernova, so I want to be able to read it myself.

...

I just checked--that statement came from the Fox News article, not the Berkeley release and it is not a quote from the researcher. A reporter wrote it.

I know I'm being picky, but I can't believe a conclusion made in a news article until I have proof that it came from the scientists.

If I am overlooking something--please enlighten me!:)

George
2009-Jun-12, 03:26 AM
Sorry to be picky, but I just don't see that statement in that article. (Are my eyes deceiving me?) Nope, it was my error. I was looking at several releases and had Berkeley on the brain, apparently.


I just checked--that statement came from the Fox News article, not the Berkeley release and it is not a quote from the researcher. A reporter wrote it. Yep, and thanks for the correction. [I've edited the prior posts, too.]


I know I'm being picky, but I can't believe a conclusion made in a news article until I have proof that it came from the scientists. That's wise since I doubt anyone in history has ever correctly predicted that a certain star would go supernova. Trinitree may be the first. :)

Maybe someday core compositions can be determined, which would make the predictions much more... iron clad. :)

Intenceman
2009-Jun-12, 05:45 AM
I saw a bright light in the western sky just before sundown. Too small to be the moon, way too bright to be a normal star, and I've never seen any planet, even Venus that bright. I thought weather balloon reflecting the sun- but it was very bright for that, or maybe a star went supernova. I still don't know what it was, but imagine my surprise when I read this article. I'm not saying it was Betelgeuse, but it would be kind of cool if it was.

Jens
2009-Jun-12, 05:54 AM
Betelgeuse will be big news when it goes. It's not something that nobody but you will notice.

Intenceman
2009-Jun-12, 06:09 AM
Betelgeuse will be big news when it goes. It's not something that nobody but you will notice.
I didn't say it was. It was the COINCIDENCE that surprised me.

Jens
2009-Jun-12, 06:32 AM
but it would be kind of cool if it was.

Sorry, but I took that to mean that you thought it might be.

tdvance
2009-Jun-12, 08:32 PM
I believe Betelgeuse is currently in the daytime sky. If it happens about now, we should see something that looks like an extra-bright venus in the daytime sky.

But remember, in astronomy, something that is about to happen can take thousands of years.

Don Alexander
2009-Jun-12, 09:45 PM
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
2009-Jun-12, 10:27 PM
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.

Argos
2009-Jun-12, 11:15 PM
It's an interesting point, because it illustrates how confusing it can be when people say, "it's about to blow up." What they really mean is probably, "it blew up at a time when it's about to appear to us that it's blown up," but it can be confusing because people aren't necessarily talking about the same thing.

Yeah, but I was referring to the fact that the data are inconclusive as to the time frame. It is a variable, and the fluctuations observed donīt seem to point to a drastic regime change. Researchers point out that the increased shhrinkage might be only a result of observation errors. Based on statistics, Iīd say it is still there [It would be nice if it did explode in 1400, so we could enjoy a cool show one of these days].

Jerry
2009-Jun-13, 02:01 AM
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.

Don Alexander
2009-Jun-13, 06:38 AM
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 (http://adsabs.harvard.edu/abs/2008AJ....135.1430H). Alas, it is NOT on astro-ph (silly, silly - the paper we are actually discussing in this thread (http://adsabs.harvard.edu/abs/2009ApJ...697L.127T) 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...

chornedsnorkack
2009-Jun-13, 10:05 AM
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.

Yes, but it is visible when looking carefully. There are other naked eye nebulae - Orion nebula, Praesepe and many other open clusters, Omega Centauri and 47 Tucanae.

Also, Crab is magnitude +8,4 now, 955 years after explosion. What was the total magnitude of Crab in 1154? In 1064?

Betelgeuse is about 10 times closer, thus 5 magnitudes brighter than Crab - about 250 times closer and thus 12 magnitudes brighter than Sanduleak.

How long did the Sanduleak take to brighten from its previous magnitude (12, which means a bit over 100 000 times brighter than Sun) to its peak brightness (+2,9)?

How bright is Sanduleak now (22 years after burst)?

Crab is now about 1000 times brighter than the Sun.

George
2009-Jun-13, 01:34 PM
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.

Don Alexander
2009-Jun-13, 07:06 PM
How bright is Sanduleak now (22 years after burst)?

The light curve decay has flattened at about 20th magnitude. Though I'd expect the SNR to brighten with time, as more and more outflowing matter collides with the old ring around the star (the outer parts of the shock front are already lighting it up).


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.
Nope, definitely no line emission. The only thing in that spectral range which could be really powerful is Lyman alpha and C IV, and I've never heard of those being in emission in supernovae... Though I guess FUV spectra of SNe are very rare, since hardly any are bright enough to yield sufficient S/N. Also, there's no dedicated big FUV mission flying. GALEX and Swift are small, and HST has lost (though hopefully regained now!) STIS...

Are there SEDs of any of these? I would assume non-thermal emissions would not be that close to a blackbody.
Can't find a direct SED now... Here's the PDF (http://arxiv.org/pdf/astro-ph/0603279v3) of the Campana et al. Nature paper (free arXiv-Version) on the SN 2006aj shock break-out. Check out figure 2. The color coding is a bit suxky. The V (visual) band, the longest Swift UVOT measures, is in red. Red is the blue B band... The SN itself (the late bump) is seen to peak in B and V, whereas the FUV flash is brightest in the UVW2 band at 188 nm (yellow points), whereas the SN itself is clearly strongly damped in the UV.
And the UV flash is a thermal component. The top panel, showing X-ray data, shows, in the left side, the total x-ray emission (thick points) and the rising thermal X-ray component (open points).

chornedsnorkack
2009-Jun-13, 07:47 PM
The light curve decay has flattened at about 20th magnitude. Though I'd expect the SNR to brighten with time, as more and more outflowing matter collides with the old ring around the star (the outer parts of the shock front are already lighting it up).


Wow, thatīs dim. It seems 100 times dimmer than Crab!

Don Alexander
2009-Jun-13, 08:24 PM
Remember that it's just two decades old, not a 1000 years. Still a lot to come.

Rhaedas
2009-Jun-14, 12:03 AM
Just curious, and maybe I missed it somewhere, but if the observations before and now were close to correct, and we have seen a 15% decrease in size...

Is this what we would expect with current theory of a supernova collapse rate? Or is there not such a thing as a "standard" rate of collapse?

danscope
2009-Jun-14, 01:20 AM
I was wondering....does the composition of the star affect the schedule for going nova? Curious.
Has a nearby...relatively....star gone nova in modern times...underscientific scrutiny?
Best regards, Dan

tdvance
2009-Jun-14, 01:30 AM
No--the last naked-eye supernova was a couple hundred years ago. We are, statistically speaking, overdue. But since stars don't communicate with each other (as far as we know), that doesn't mean one will come sooner any more than flipping a fair coin 9 times and getting heads means the next flip has a greater than 50-50 chance of being tails.

chornedsnorkack
2009-Jun-14, 07:42 AM
No--the last naked-eye supernova was a couple hundred years ago.

No - 22 years.

tdvance
2009-Jun-14, 12:41 PM
No - 22 years.

ok, I looked it up, SN1987A in the large Magellanic cloud was visible to the naked eye.

I was thinking of "Milky Way" I guess--we expect about one every 50 years, but actually somewhat longer because we can't see all of the Milky Way from the inside, but haven't had any since 1604, which Galileo used to argue against the immutability of the celestial sphere.

George
2009-Jun-14, 02:18 PM
What percentage of the Milky Way are we now able to detect [visibly] a supernova? [Added: Ok, it's 100% thanks to neutrino detectors.] Prior to this, wasn't it less than half not long ago?

Don Alexander
2009-Jun-14, 06:35 PM
Just curious, and maybe I missed it somewhere, but if the observations before and now were close to correct, and we have seen a 15% decrease in size...
Is this what we would expect with current theory of a supernova collapse rate? Or is there not such a thing as a "standard" rate of collapse?

Actually (reading the posts above) I'm not even sure that the original authors even inferred anything about a supernova...

Anyway, if a star goes supernova, it's not like you will see it to start shrinking because the core has collapsed under it (unless it's one of those hypothesized failed SNe!). It will just sit there being a merry red supergiant or Wolf-Rayet or LBV, and suddenly it will blast apart.

What seems to be implied is that this shrinking my be due to an earlier stage of core collapse, when the "ash" of the last round of fusion has accumulated into such a heavy core that it starts to contract gravitationally. And the rest of the star's matter is following it. I'm not much into stellar theory, but I also recall that such a gravitational collapse releases extreme amounts of energy, which should actually make the star expand and become brighter. This is exactly what happens when stars move up the asymptotic giant branch during first and second ascension.


I was wondering....does the composition of the star affect the schedule for going nova? Curious.
Yes and no, from what I know. The hypothesized Population III stars in the very early Universe were made almost entirely of H and He, and had no efficient cooling mechanism, meaning they grew to huge sizes, possibly up to 1000 solar masses. This strongly affects the way the star evolves. The extremely massive ones are actually supposed to collapse quite rapidly into black holes without exploding, while the one of ~ 150 - several 100 M_O will form pair-production supernovae, ultra-powerful explosions which leave no remnant whatsoever, like Type Ia.

Today, though, all young stars are quite "polluted" with metals. Still, late in their life, the metallicity is crucial in driving powerful winds. Very massive stars in our Milky Way mostly blow off their outer shells and become Wol-Rayet stars, while in low-metallicity galaxies (like the SMC) red supergiant are much more common.

I am, in the end, not really sure if the metallicity really has a strong effect on the speed of the fusion sequence in the core (excepting Pop III which had no CNO cycle).

Has a nearby...relatively....star gone nova in modern times...underscientific scrutiny? Best regards, Dan
Yes, SN 1987A, see above. Though of course astronomical technology has developed vastly compared to even 22 years ago.
Some months ago, a radio supernova was found near the core of the Milky Way that is 135 years old, the newest supernova we know of, but it was utterly invisible to the naked eye.
There is debate if Cassiopeia A, which exploded in 1680, was visible to the naked eye, if so, it was extincted down to like 4th magnitude, very unspectacular.
Otherwise, you have Kepler's SN in 1604, and Tycho's in 1572.

Before that, there was one in the late 12th century that seems to have reached mag 0, I also recall it was detected from isotope ratios in the Greenland ice sheet.

And of course the two great SNe 1054 (Crab) and 1006 (Lupus).

Before that, according to Wikipedai, three in 185, 386 and 393 (unfair!). There was either a 600 year hole, or a problem with record-keeping then...

Also, we are overdue for a SN from Andromeda, the last known was 1885, and I think if a newer one had occured in a heavily obscured region, it would hve been detected as an X-ray and radio source by now...

Otherwise, the nearest one in recent years was 1993J in M81, that one exceeded tenth magnitude.

mike alexander
2009-Jun-14, 07:46 PM
Unless it exploded five hundred years ago.

...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).

A similar question came up in Fred Hoyle's novel The Inferno, where the Milky Way briefly becomes a quasar/Seyfert galaxy. The protagonist Cameron shows that since the human eye cannot resolve a point source to an image of less than ten arcseconds or so, some reasonable assumptions about absolute brightness result in an intensity 100 times less than the equivalent Sun or more, too low to harm vision.

If someone could confirm that, I'd appreciate it.

eburacum45
2009-Jun-14, 09:34 PM
This thread might be of interest.
http://www.bautforum.com/space-astronomy-questions-answers/85865-maximum-magnitude-safe-see.html

What saves us from incurring tiny points of retinal damage from all the stars in the sky is diffraction limitation: once the solar disc gets down to about one minute of arc in diameter, it stops getting smaller. At that point, the apparent surface brightness starts to decline with increasing distance (as less light is diffracted to cover the same size of spot), and so the level of retinal illumination goes down with increasing distance, quickly reaching safe levels. That's even safer than the limit in Hoyle's story, I think.

AndrewJ
2009-Jun-14, 11:10 PM
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?

tdvance
2009-Jun-15, 12:48 AM
yeah, that's right, Aldebaran is the eye of the bull.

rommel543
2009-Jun-15, 06:43 PM
OK so when the big B does go there is a possibility that it could develop into a black hole. If a black hole did occur, how much of a light show would we really see? The initial explosion would push much of the material away , but I would think that much of it would fall back in because of the gravitational effect. Instead of a huge light show we would only see something the brightness of a nova.

tdvance
2009-Jun-15, 09:08 PM
at 20 solar masses, it would be a sure thing that it becomes a black hole (according to a book I have from about 1990 or so--we might know better now).

But, that doesn't mean much of it would fall back--strong in the force is gravity...but not that strong (unless you are really close to the event horizon).

Since it is gravitational energy that fuels the supernova outburst (the collapse of the core turns lots of potential energy, and matter, into kinetic energy, including radiation), I'd think a star becoming a black hole would be a brighter supernova than one becoming only a neutron star.

Don Alexander
2009-Jun-15, 09:09 PM
OK so when the big B does go there is a possibility that it could develop into a black hole. If a black hole did occur, how much of a light show would we really see? The initial explosion would push much of the material away , but I would think that much of it would fall back in because of the gravitational effect. Instead of a huge light show we would only see something the brightness of a nova.

You might want to read up on how supernovae actually work...

Now, as I mentioned before, there are theories that predict failed supernovae - check out this paper (http://arxiv.org/abs/0802.0456) for more details on that. In such a case, the star would spiral into the black hole with also no explosive signal.

On the other hand, the best understanding of gamma-ray bursts we have today tells us that massive stars can explode, producing a black hole and a very powerful supernova at the same time.

Once the supernova explosion is actually launched (a process that obviously occurs but is still not really understood), there is no stopping the expansion.

Remember, black holes do not increase gravity!! If you have three solar masses within a radius x, this will have an (assuredly strong) surface gravity - if you collapse those three solar masses into a black hole the gravity at radius x remains unchanged!! Any matter that reaches escape velocity from three solar masses at radius x will escape from the black hole just as readily as from an uncollapsed core.

Fiery Phoenix
2009-Jun-18, 10:00 AM
I think they really mean that the explosion is about to reach us, indicating that it has already occurred. Either way, I would absolutely love to witness the event.

On a related note, I feel curious to see what Orion would look after the explosion of Betelgeuse.

chornedsnorkack
2009-Jun-18, 10:57 AM
Once the supernova explosion is actually launched (a process that obviously occurs but is still not really understood), there is no stopping the expansion.

Remember, black holes do not increase gravity!! If you have three solar masses within a radius x, this will have an (assuredly strong) surface gravity - if you collapse those three solar masses into a black hole the gravity at radius x remains unchanged!! Any matter that reaches escape velocity from three solar masses at radius x will escape from the black hole just as readily as from an uncollapsed core.

Overcome gravity yes, but accelerate?

Once the core has collapsed AND produced an explosion, the bulk of the star is still there, all around the core and the explosion. The explosion must somehow accelerate it as well.

If the core turned into a neutron star, the neutron star will support pressure by its great stiffness and it is immensely hot, assuring huge pressure of gamma rays all between the neutron star and the explosion, which keeps accelerating the explosion. The matter density between the neutron star and explosion may be low, but pressure of the radiation and the little matter is very high.

However, if a black hole were to form, it would support no pressure and emit no heat. The event horizon would be the path of least resistance for the contents of the interior of the star, so as the driving pressure is released from behind, the explosion should weaken and eventually stop and fall back into the hole...

Don Alexander
2009-Jun-18, 11:40 AM
Basically, this is a good point, and since supernovae are still not "exploding in the lab", I don't think anyone can truly answer that.

But one thing you seem to be forgetting is angular momentum. The matter doesn't just fall into the star, it's going to form a viscous accretion disk in the equatorial plane, and it must remove angular momentum to actually cross the event horizon. This is done by drag (thus, a viscuous accretion disk), which heats the disc up to MK temperatures, releasng copious amounts of radiation. This may then power the outward acceleration of most of the star's shell.

rommel543
2009-Jun-18, 01:36 PM
You might want to read up on how supernovae actually work...

Now, as I mentioned before, there are theories that predict failed supernovae - check out this paper (http://arxiv.org/abs/0802.0456) for more details on that. In such a case, the star would spiral into the black hole with also no explosive signal.

On the other hand, the best understanding of gamma-ray bursts we have today tells us that massive stars can explode, producing a black hole and a very powerful supernova at the same time.

Once the supernova explosion is actually launched (a process that obviously occurs but is still not really understood), there is no stopping the expansion.

Remember, black holes do not increase gravity!! If you have three solar masses within a radius x, this will have an (assuredly strong) surface gravity - if you collapse those three solar masses into a black hole the gravity at radius x remains unchanged!! Any matter that reaches escape velocity from three solar masses at radius x will escape from the black hole just as readily as from an uncollapsed core.

So reading the paper (which gave me a headache because of all the antiquated citations) there is a possibility that a star can turn into a BH without going nova just not a decreased nova. It's boom or no boom.

So what would happen if Eta Carinae transitioned directly into a a spinning BH. I know it's been stated that the gravitational influence doesn't change when the star collapses but would the increase spin cause the surrounding nebula to either be blown away or pulled into the accretion disk? What is the reach of the frame dragging caused by the spinning?

Dgennero
2009-Jun-19, 01:58 PM
It says in the Berkeley release that the shrinking (of Betelgeuse) is smooth but accelerating.
This needs to be watched (how many data points do we have from the past btw.?) closely so that we can get a graph.
We could then extrapolate (or, if the graph closely resembles a known function, use calculus) to see when the diameter would become critically small - small enough for a violent rebound (supernova).
Does anybody know if the "rebound-diameter", which should be a function of stellar mass, is known?
I hope Betelgeuse does us the favor, it would be the first close supernova-event in the space age and provide a wealth of data - and we'd see it *as it develops*, not when it is already happening, which means it would be easier for us to predict such an event in the future.
My favorite runner-up is the semiregular mu Cephei, this one and maybe a handfull others within 1-2 kpc also need watching.

Fiery Phoenix
2009-Jun-19, 03:32 PM
^ Something tells me it's going to blow up in our lifetime and we'll get to witness it ourselves. Just how awesome would that be? And, of course, how lucky we would be!

antoniseb
2009-Jun-19, 03:33 PM
Does anybody know if the "rebound-diameter", which should be a function of stellar mass, is known?...

I don't know the answer here, but I can tell you that what we are looking at is the photosphere, which is huge and sparse. I believe that if you were to calculate the density of the gas in that outer part of the star, it would be a better vacuum than we can make on Earth. This diameter shrinking 15% is not something that will result in some kind of rebound. It is compression deep within that we will never see with photons that is important.

Ampatent
2009-Jun-20, 02:47 PM
Am I the only one that is distraught over the pronunciation of Betelgeuse? Beetle juice just sounds so weird... I'd much rather say beetle guys.

Fiery Phoenix
2009-Jun-20, 03:16 PM
Am I the only one that is distraught over the pronunciation of Betelgeuse? Beetle juice just sounds so weird... I'd much rather say beetle guys.

Pronunciation is one of the most tentative things in astronomy as a whole anyway. I think it would be a wise thing if the IAU devote some time for this particular issue and see what they can do about it. Lots of people just pronounce stars and moons' names the way they want, which, if you think about it, can actually lead to undesired consequences at times.

Dgennero
2009-Jun-20, 04:54 PM
...especially if you are talking about sending a probe into Uranus :)
For this one, I adopted the pronunciation "you ran us" as suggested somewhere way back in another thread.
Betelgeuse can be pronounced "bettl-juice", which Merriam Webster has as an option and I also found it in this pronunciation guide: http://www.wsanford.com/~wsanford/exo/pronunciation_guide.html
In my native Germany there is an alternative spelling "Beteigeuze" with the pronunciation "bay-tie-GOY-tsuh", and the French probably say "bettl-ZHIRS".
By the time the English pronunciation is finally settled, we'll probably have no more reason to argue about it :(

Fiery Phoenix
2009-Jun-20, 05:00 PM
It's not just Betelgeuse, though. Tens of other celestial objects have names that are tentatively pronounced. Take Saturn's moons as an example, such as Iapetus, Rhea, etc. Moreover, I've met people who don't know how to pronounce Rigel.

The only remedy for this is to decide on a single, settled pronunciation for these words, and I think that would be the IAU's job.

Buttercup
2009-Jun-20, 05:13 PM
Everytime I see this thread, I laugh. :lol: --BOOM! :D Lol!

tdvance
2009-Jun-20, 08:03 PM
Am I the only one that is distraught over the pronunciation of Betelgeuse? Beetle juice just sounds so weird... I'd much rather say beetle guys.

As I said in the "geek argument" thread, it's Bet - el - Juice, and nothing else!!!

Buttercup
2009-Jun-20, 09:11 PM
Beatle Juice. :D It's what The Fab Four had every morning with bacon and eggs. :p

Jens
2009-Jun-22, 02:09 AM
The only remedy for this is to decide on a single, settled pronunciation for these words, and I think that would be the IAU's job.

This is a question I sometimes ask, but do you mean the proper pronunciation in English, or in general, i.e. in all languages? If you mean the latter, you will run into difficulties, because just taking Rigel, there are many languages in the world that have no "r" sound, and there are also many languages where it is not permitted to end a word with a consonant (many Polynesian languages are like this). So I just checked on Wikipedia, so I might be wrong, but apparently the correct pronunciation in English is something like "Raijel," where in Japanese the correct pronunciation is "Riggeru." Are you suggesting making an ideal pronunciation in International Phonetic Alphabet, and then saying that local languages should adopt it to their phonology? Or are you just saying that the IAU should set the pronunciation in English?

And not in response to this comment, but I really like the name Betelgeuse. In fact, I really like the names of most stars that derive from Arabic. There's something exotic about names like Aldebaran and Rigel.

Fiery Phoenix
2009-Jun-22, 05:37 AM
This is a question I sometimes ask, but do you mean the proper pronunciation in English, or in general, i.e. in all languages? If you mean the latter, you will run into difficulties, because just taking Rigel, there are many languages in the world that have no "r" sound, and there are also many languages where it is not permitted to end a word with a consonant (many Polynesian languages are like this). So I just checked on Wikipedia, so I might be wrong, but apparently the correct pronunciation in English is something like "Raijel," where in Japanese the correct pronunciation is "Riggeru." Are you suggesting making an ideal pronunciation in International Phonetic Alphabet, and then saying that local languages should adopt it to their phonology? Or are you just saying that the IAU should set the pronunciation in English?

And not in response to this comment, but I really like the name Betelgeuse. In fact, I really like the names of most stars that derive from Arabic. There's something exotic about names like Aldebaran and Rigel.

The former. But that's only because of the fact that English is the number one language in the world right now. I'm sure the IAU could do it if they wanted.

Ampatent
2009-Jun-22, 08:06 AM
And not in response to this comment, but I really like the name Betelgeuse. In fact, I really like the names of most stars that derive from Arabic. There's something exotic about names like Aldebaran and Rigel.

I don't really have a problem with the name, it's just the pronunciation that irks me. Every time I hear it I think of that (http://www.imdb.com/title/tt0094721/) movie from the 80's.

H4wkeye
2009-Jun-22, 11:30 AM
I think they really mean that the explosion is about to reach us, indicating that it has already occurred. Either way, I would absolutely love to witness the event.

On a related note, I feel curious to see what Orion would look after the explosion of Betelgeuse.

Wait.So if it already occurred,how come no telescope or w/e spotted it yet?Cuz of the distance that light has to travel or? :confused:

Tog
2009-Jun-22, 11:58 AM
Wait.So if it already occurred,how come no telescope or w/e spotted it yet?Cuz of the distance that light has to travel or? :confused:
Yup.

You ever see a live fireworks display? You'll see the flash from one of them, then about a quarter second later, you hear the "boom". Sound takes time to get to you. So does light. We are around 620 light years from the star. That means that we see it as it existed 620 years ago. A telescope won't change that, but it will let us see it in more detail (if it's really big). What we see won't change, only the way we see it.

Because of the distance, it could have exploded 600 years ago, but we won't see it happen for another 20 years. Just like the way that a firework explodes, and the sound takes some time to get to us.

H4wkeye
2009-Jun-22, 12:47 PM
Yup.

You ever see a live fireworks display? You'll see the flash from one of them, then about a quarter second later, you hear the "boom". Sound takes time to get to you. So does light. We are around 620 light years from the star. That means that we see it as it existed 620 years ago. A telescope won't change that, but it will let us see it in more detail (if it's really big). What we see won't change, only the way we see it.

Because of the distance, it could have exploded 600 years ago, but we won't see it happen for another 20 years. Just like the way that a firework explodes, and the sound takes some time to get to us.

Ah i see,its more clear to me now,thanks.So basically we are seeing those distant objects with a big "lag".Events already occurred many years ago but we are seeing it as the light reaches us.

pumpkinpie
2009-Jun-22, 01:47 PM
My 2 cents about pronunciation....I don't think it makes that much of a difference, as long as everyone knows what celestial object you are talking about!

Fiery Phoenix
2009-Jun-22, 02:14 PM
Ah i see,its more clear to me now,thanks.So basically we are seeing those distant objects with a big "lag".Events already occurred many years ago but we are seeing it as the light reaches us.

Precisely.


My 2 cents about pronunciation....I don't think it makes that much of a difference, as long as everyone knows what celestial object you are talking about!

It can still be confusing, though.

Ara Pacis
2009-Jun-23, 05:41 AM
How fast does gravity propogate? Would we be theoretically able to detect the shift in mass from an exploding star, such as bee/beh/bay-tel-juice/geece/gayce/gice?

NEOWatcher
2009-Jun-23, 12:06 PM
How fast does gravity propogate? Would we be theoretically able to detect the shift in mass from an exploding star, such as bee/beh/bay-tel-juice/geece/gayce/gice?
Speed of light.
But; I'm not sure what you mean by "shift" in mass, it's all still there and , just more spread out. At this distance, the mass would have to travel quite a distance before we can detect any gravity effect. (if at all?)

tdvance
2009-Jun-23, 07:55 PM
And of course, the gravity effect would be so weak we'd have a better chance detecting light or neutrinos first. Our gravity wave detectors are made for huge things like binary black holes about to collide.

Ara Pacis
2009-Jun-23, 08:50 PM
Speed of light.
But; I'm not sure what you mean by "shift" in mass, it's all still there and , just more spread out. At this distance, the mass would have to travel quite a distance before we can detect any gravity effect. (if at all?)

That's what I was wondering, if we could detect the shift in mass from the expanding cloud of mass, perhaps through parallax, or not. Do we know through theory or observations that gravity propogates at the speed of light?

Ara Pacis
2009-Jun-23, 08:53 PM
And of course, the gravity effect would be so weak we'd have a better chance detecting light or neutrinos first. Our gravity wave detectors are made for huge things like binary black holes about to collide.

But could we use some sort of interferometry to detect/resolve gravity better?

Also, it's a bit confusing because the term "gravity wave" seems to have two meanings. One is a gravity-balancing density shift and the other would seem to refer to gravitons or something.

tdvance
2009-Jun-24, 01:23 AM
In this case, I mean, by gravity wave, that which would be, under wave-particle duality, equivalent to the graviton, in other words, ripples propagating in spacetime.

LIGO, the biggest gravity wave detector, does use interferometry, but still, I doubt it would detect a supernova.

antoniseb
2009-Jun-24, 12:46 PM
I welcome correction on this from anyone who is an expert in LIGO, LISA, etc (I am not one), but I have the impression that our detectors are about one quarter the wavelength of the size wave they are best tuned to detect. Since the arms of LIGO are about 2 km, they best detect waves about 8 km long (straight on, somewhat longer obliquely).

This is pretty small for astrophysical phenomena. Perhaps the only things this has a shot at detecting are formations of stellar mass black holes, the compact object collisions that are presumed to cause the sub-second GRBs, and to a lesser degree the stellar core collapse that leads to neutron star formation.

If Betelgeuse (very nearby as these things go) forms a black hole, LIGO should detect it. ... so would all of our neutrino detectors.

Don Alexander
2009-Jun-24, 01:15 PM
A definite yes on the neutrino signal, if it has anything like the luminosity of SN 1987A, it should stick out like a sore thumb - especially since we have a lot more (and more sensitive) detectors than 22 years ago.

And, yes, there's a definite signal expected from the final collapse phase of the stellar core in a supernova (not really from the expanding explosion later, that would be much too weak), and I'm reasonably sure LIGO and other interferomtric gravity wave detctors are in the range (~ kilohertz) where those signals are expected to peak. What I don't know is how strong such a signal is expected to be. Definitely fainter than a neutron star neutron star merger, though. I know those should be detectable out to the Virgo cluster.

chornedsnorkack
2009-Jun-24, 09:38 PM
If Betelgeuse (very nearby as these things go) forms a black hole, LIGO should detect it. ... so would all of our neutrino detectors.

Um, photons cannot get out of an event horizon - and neither can neutrinos. So neutrino detectors can observe formation of neutron star, but not black hole.

Regarding gravity waves, their emission requires quadrupole moment. Black hole formation does not require that.

antoniseb
2009-Jun-24, 11:13 PM
Um, photons cannot get out of an event horizon - and neither can neutrinos. So neutrino detectors can observe formation of neutron star, but not black hole.

Do you think that the neutrinos are released before or after the formation of the event horizon? Did SN1987a form a black hole? Some scientists think so.

tdvance
2009-Jun-25, 12:26 AM
According to Kip Thorne, the formation of a black hole converts about a 1/10 solar mass into energy--mostly in photons, but also the kinetic energy of neutrinos--that doesn't become part of the black hole.

Cruithne3753
2009-Jun-25, 05:33 PM
So if we are seeing the prelude to the big B blowing, what's the estimated timescale?

Dgennero
2009-Jun-25, 05:57 PM
To answer that, we need to see how much the contraction accelerates and if this contraction really is "the final one", but *if* it is, since B has shrunk by 1% of its diameter per year and this seems to be accelerating, having lost now 15% of its original diameter, some time before 2094 is the deadline, but probably much earlier.

antoniseb
2009-Jun-25, 06:03 PM
So if we are seeing the prelude to the big B blowing, what's the estimated timescale?

Why would the change in size of the outer envelope be obviously connected to the collapse of the inner core?

Dgennero
2009-Jun-26, 08:25 PM
It wouldn't.
But we have yet to see a star collapse, so how do we know if only the outer envelope shrinks or the star as a whole contracts?

gatorain
2009-Jun-27, 04:20 AM
just look at this pic how massive the betelgeuse is...

http://i36.photobucket.com/albums/e38/nokare/beteboom.jpg

Dgennero
2009-Jun-27, 08:06 PM
And here:
http://mrbarlow.wordpress.com/2009/06/17/betelgeuse-is-shrinking/

But bigger is possible:
http://www.youtube.com/watch?v=I34FNr_peUk&NR=1

Ara Pacis
2009-Jun-29, 06:17 AM
So, if the outer bit of Betelgeuse sloughs off and becomes becomes diluted, will we have to rename it Beteljrinc? And if it forms a black hole at its core, will we then call it betelkonsentrayt?

Jens
2009-Jun-29, 06:28 AM
So, if the outer bit of Betelgeuse sloughs off and becomes becomes diluted, will we have to rename it Beteljrinc? And if it forms a black hole at its core, will we then call it betelkonsentrayt?

If it suddenly starts moving toward us in a threatening way, we could always rename it Betelstar Galactica.

trinitree88
2009-Jun-29, 03:37 PM
If it suddenly starts moving toward us in a threatening way, we could always rename it Betelstar Galactica.

Jens. Good one!:shifty::doh::lol: pete (quite original)

eburacum45
2009-Jul-01, 10:40 AM
just look at this pic how massive the betelgeuse is...

http://i36.photobucket.com/albums/e38/nokare/beteboom.jpg

That second image can't be correct; the Eta Carinae Homunculus nebula is on the order of a light year across, while Betelgeuse is a bit more than a light hour across.

NEOWatcher
2009-Jul-01, 11:47 AM
That second image can't be correct; the Eta Carinae Homunculus nebula is on the order of a light year across, while Betelgeuse is a bit more than a light hour across.
Sure; now it is, but maybe that's the nebula's baby picture. :whistle:

Tog
2009-Jul-01, 12:33 PM
Sure; now it is, but maybe that's the nebula's baby picture. :whistle:
They grow up so fast.
*snif*

chornedsnorkack
2009-Jul-01, 05:50 PM
Eta Carinae at about 8000 lightyears is 1,25 times farther, and thus 0,5 magnitudes brighter than Crab - which means that it is 12,5 times farther and 5,5 magnitudes brighter than Betelgeuse.

If Eta Carinae were located at the position of Betelgeuse, it should have been brighter than Siriusī -1,5 steadily since 17th century, with occasional outbursts to -3,5 - then after 1820, brightened to -6,3 in April 1843. And dimmed to about magnitude 2,4 between 1900 and 1940. Now brightening to -0,8 again...

George
2009-Jul-01, 11:11 PM
Here's one y'all might like.

Tell me how long it would take for a 727 jet liner to fly non-stop the same distance as the circumference of the Sun and also of Betelgeuse? [Use a cruising speed of 900 km/hr.]

Dgennero
2009-Jul-02, 05:54 PM
Sun: ca. 202.5 days.
Betelgeuse at 936 x R sun: ca. 520 yrs.
Bon voyage :)

George
2009-Jul-03, 01:36 AM
Sun: ca. 202.5 days.
Betelgeuse at 936 x R sun: ca. 520 yrs.
Bon voyage :) Yep. :)

bmpbmp
2009-Jul-20, 04:41 PM
I was under the impression that this is to far to affect us but as per this article it may not be.

Which info is right

Thank You

http://www.rense.com/general86/boom.htm

Celestial Mechanic
2009-Jul-20, 05:13 PM
I was under the impression that this is too far away to affect us but as per this article it may not be.

Which info is right? {Snip!}
Consider the source. If rense.com were printed instead of posted on the Internet, it would be lining bird cages. :D

Glom
2009-Jul-21, 05:16 AM
So we can expect a daytime star to appear soon?

But it won't just appear like snap, it'll brighten over a few days?

Grashtel
2009-Jul-30, 11:38 AM
So we can expect a daytime star to appear soon?

But it won't just appear like snap, it'll brighten over a few days?
Soon in astronomical terms, so any time in the next few million years or so. Seeing a supernova up close should be very interesting, though personally I'd feel better if it would back up a couple of hundred light years (not that its likely to do anything significant to Earth).

vonmazur
2009-Jul-30, 08:32 PM
...especially if you are talking about sending a probe into Uranus :)
For this one, I adopted the pronunciation "you ran us" as suggested somewhere way back in another thread.
Betelgeuse can be pronounced "bettl-juice", which Merriam Webster has as an option and I also found it in this pronunciation guide: http://www.wsanford.com/~wsanford/exo/pronunciation_guide.html
In my native Germany there is an alternative spelling "Beteigeuze" with the pronunciation "bay-tie-GOY-tsuh", and the French probably say "bettl-ZHIRS".
By the time the English pronunciation is finally settled, we'll probably have no more reason to argue about it :(

Meine Herren; Is not the real name of this star "Baht Al Juse" meaning "Shoulder of the Giant"?? (In Arabic)..... I do love the German/French/NipponGo/ and other ways to say it...

In any case, this is most interesting....I am sure that it can wait til winter to go, so we can see it at night here in the US...

Dale in AL

sohh_fly
2009-Jul-30, 08:45 PM
If it suddenly starts moving toward us in a threatening way, we could always rename it Betelstar Galactica.

How real of a possibilty is that or not?
would that be the closest "BH" to us if it should go?

Glom
2009-Jul-30, 10:18 PM
If Betelgeuse did blew up tomorrow, how much of an event would it be outside the astronomical community? Would it get more than just a big mention on the science pages of the major news outlets? The fact that Betelgeuse is part of Orion might give it a boost since everyone knows the constellation Orion thanks to its equatorial position, its prominent and distinct form and mostly importantly, the fact that it was featured in Men in Black.

robross
2009-Jul-31, 12:32 AM
If Betelgeuse did blew up tomorrow, how much of an event would it be outside the astronomical community? Would it get more than just a big mention on the science pages of the major news outlets? The fact that Betelgeuse is part of Orion might give it a boost since everyone knows the constellation Orion thanks to its equatorial position, its prominent and distinct form and mostly importantly, the fact that it was featured in Men in Black.

It would be huge! (Please let's all resist the urge to say "if it blew up tomorrow we wouldn't see it for 640 years. Let's assume the OP meant 'if it appeared to us to blow up tomorrow.')

The world is already conditioned to think of total solar eclipses and cometary approaches as very rare, special things, and they always get a lot of press when they occur. So I have no doubt the media would in fact do a good job of explaining how rare an event this is, and how anyone that can should take advantage of the viewing opportunity.

Rob

matthewota
2009-Jul-31, 02:49 AM
It is better to quote from the original Berkeley news release than from a second source, especially when it comes to a scientific subject.

Tobin Dax
2009-Jul-31, 04:09 AM
If Betelgeuse did blew up tomorrow, how much of an event would it be outside the astronomical community? Would it get more than just a big mention on the science pages of the major news outlets? The fact that Betelgeuse is part of Orion might give it a boost since everyone knows the constellation Orion thanks to its equatorial position, its prominent and distinct form and mostly importantly, the fact that it was featured in Men in Black.
If it went off while it was visible in daylight, I'd think that it would be all over. Six months ago or so, Venus was of general public interest. Wouldn't something similar be true of an object (a supernova, no less) that was visible during the day.

Disclaimer: I'm being lazy and not checking the magnitude of said supernova or when Betelgeuse rises and sets tomorrow.

Jerry
2009-Aug-03, 01:02 AM
Meine Herren; Is not the real name of this star "Baht Al Juse" meaning "Shoulder of the Giant"?? (In Arabic)..... I do love the German/French/NipponGo/ and other ways to say it...

In any case, this is most interesting....I am sure that it can wait til winter to go, so we can see it at night here in the US...

Dale in AL

Actually, the t and s are silent and the l is cleft: beef au jour...

Glom
2009-Aug-03, 02:11 PM
What will we put on the epitaph?

mantiss
2009-Aug-03, 04:17 PM
What will we put on the epitaph?
I think having a superb SN remnant and/or nebula makes any epitaph quite meaningless ;)

Glom
2009-Aug-03, 04:45 PM
I think having a superb SN remnant and/or nebula makes any epitaph quite meaningless ;)

I forgot about the resulting nebula! What will it look like? How quickly will it expand?

chornedsnorkack
2009-Aug-03, 07:19 PM
I forgot about the resulting nebula! What will it look like? How quickly will it expand?

Hard to tell.

Crab is 10 times remoter, thus 5 magnitudes dimmer than Betelgeuse. In which case Betelgeuse should be -11 as supernova, and the nebula should be magnitude +3 1000 years later.

Sanduleak is 250 times remoter, thus 12 magnitudes dimmer than Betelgeuse. It was magnitude 12 - like Betelgeuse at magnitude 0 - and at maximum was +2,9 magnitude, comparable to Betelgeuse at -9. But in 22 years, it has faded away to +20, comparable to +8 at the distance of Betelgeuse or +13 at the distance of Crab.

GalacticBeatDown
2009-Aug-03, 09:31 PM
I was watching this show a few months back and I remember the host saying that when Betelgeuse goes supernova people will be able to see it in the daylight. I do not know the magnitude but it must be pretty bright to be visible in the daylight. It will be as big as a person extending their arm and putting their thumbnail over a patch of sky. So probably half the size of the Moon.

robross
2009-Aug-03, 09:52 PM
I was watching this show a few months back and I remember the host saying that when Betelgeuse goes supernova people will be able to see it in the daylight. I do not know the magnitude but it must be pretty bright to be visible in the daylight. It will be as big as a person extending their arm and putting their thumbnail over a patch of sky. So probably half the size of the Moon.

Well, no. It will still be a point source in the sky, but it will be brighter than the moon, i.e., take the surface brightness of the moon and condense it down to a point in the sky. That is why it will be so noticeable.

Rob

GalacticBeatDown
2009-Aug-03, 11:37 PM
Well, no. It will still be a point source in the sky, but it will be brighter than the moon, i.e., take the surface brightness of the moon and condense it down to a point in the sky. That is why it will be so noticeable.

Rob

Could you post an article or a website as to where you got your information possibly? I could be wrong but I want to make sure.

Glom
2009-Aug-03, 11:39 PM
Orion is in the daytime sky at the moment, isn't it? Everyone keep a look out.

What was that thing by the Moon tonight?

robross
2009-Aug-04, 12:43 AM
Could you post an article or a website as to where you got your information possibly? I could be wrong but I want to make sure.

It's in this very thread.

"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."

http://www.bautforum.com/astronomy/89326-betelgeuse-betelgeuse-betel-boom.html#post1506518

Also, common sense exercise : The star is currently a point source in the sky. When it goes supernova, it will *shrink* to be much much smaller in diameter than it is now. What makes you think that will make it look *larger* in the sky than it does now?

Rob

GalacticBeatDown
2009-Aug-04, 01:12 AM
Thanks robross that clarified it for me. I guess I was mislead with what I saw. Yes, I know common sense that it would shrink but I was thinking of if the same thing would occur with the stars that created the planetary nebula, the Crab nebula.

Jens
2009-Aug-04, 02:17 AM
Thanks robross that clarified it for me. I guess I was mislead with what I saw. Yes, I know common sense that it would shrink but I was thinking of if the same thing would occur with the stars that created the planetary nebula, the Crab nebula.

Yes, eventually it will become larger than a point source, but it will take a long time, and by that time it will have become considerably less bright, so won't be visible in the day sky anymore.

Tobin Dax
2009-Aug-04, 04:16 AM
What was that thing by the Moon tonight?
Jupiter, maybe?

chornedsnorkack
2009-Aug-04, 05:26 AM
Crab Nebula is 4x6 minutes now.

Since Betelgeuse is 10 times closer than Crab, a similar nebula in a thousand years would be 40x60 minutes. Bigger than full Moon, but dimmer... magnitude 3 is, I think, comparable to Praesepe.

How bright would the supernova be in, say, 50 years, when the nebula is 2x3 minutes and should be becoming a bit bigger than a point?

astromark
2009-Aug-04, 08:40 AM
As of at this time... There is NO indercator of any event... calm down.
We see Betelgeuse in our morning sky. It is not looking any different than it usually does. Some club members are wishing this event upon us. As I have told them...'Yes keep an eye on this' We would not want to miss it would we? BUT remember to stay scientific. When the brightening starts. We will watch.

Tobin Dax
2009-Aug-04, 04:08 PM
Jupiter, maybe?
Not Jupiter. I was outside a little later, and saw them both in the sky. The moon won't be near Jupiter for a few days yet.

matthewota
2009-Aug-04, 09:40 PM
If Betelgeuse does blow up, I'd be willing to bet it would be visible in broad daylight.

astromark
2009-Aug-05, 10:58 AM
Yes I also thought it could not have been Jupiter. Tomorrow maybe they get close... Last night it might have been Antares.
I came back to this as today's image from NASA is the first resolved star ( Beta, beta, BOOM...
Yes this just might be going to happen... lets check the star charts... its up at 2.30 am and viewable before 3am...another long night of sky watching... and a full moon... Naa lets just sleep...:)and listen to the news in the mornings...

Glom
2009-Aug-05, 02:39 PM
I really need to get myself some planetarium software. But I don't know what to get or where to get it.

tdvance
2009-Aug-05, 09:07 PM
you can use stellarium or celestia for free (google for both).

timb
2009-Aug-05, 09:29 PM
It's in this very thread.

"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."

http://www.bautforum.com/astronomy/89326-betelgeuse-betelgeuse-betel-boom.html#post1506518



Those figures don't add up. An M=-17 event at 197 pc would be magnitude -10.5, which is considerably dimmer than the average full moon (-12.7).

StupendousMan
2009-Aug-05, 09:43 PM
Those figures don't add up. An M=-17 event at 197 pc would be magnitude -10.5, which is considerably dimmer than the average full moon (-12.7).

He is referring to the surface brightness of the source. If you took all the light of the full moon and compressed it into a tiny point, the surface brightness would go way up. One measure of the danger of a bright light source is its surface brightness, because that determines the flux of energy focused onto a point on the retina.

Big bright light source will be spread over many retinal cells. Small bright light source sits on a small number of retinal cells. Small bright light source more dangerous.

timb
2009-Aug-05, 10:14 PM
He is referring to the surface brightness of the source.

He referred to the magnitude and claimed it should exceed the brightness of the full moon by one or two magnitudes.

Starfury
2009-Sep-05, 03:39 PM
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.

At least the normally sensationalistic Fox News ended the article by saying we'd be 'perfectly safe'.

danscope
2009-Sep-05, 06:23 PM
Yep, fox nooze , the journalistic laughing stock of the day, maybe all time.
I have never seen such rubbish peddled as hrumpf....fact.
You will never find a more wretched hive of scum and villainy.

Glom
2009-Sep-06, 02:52 PM
I saw Betelgeuse the other night. Seemed normal... for the moment.

danscope
2009-Sep-06, 06:22 PM
Yes, I shouldn't think Betelgeuse will deviate from it's order. We should rest easy on that.
Best regards,
Dan

Jeff Root
2009-Sep-06, 08:36 PM
Not Jupiter. I was outside a little later, and saw them both in the sky.
The moon won't be near Jupiter for a few days yet.
Does my sky program need updating? I get that the Moon passed
Jupiter on September 2, less than two days before you wrote this.

I saw them early in the morning of the 3rd or the 4th. The full Moon
was east of Jupiter. I didn't use binoculars, but it looked like Jupiter.

-- Jeff, in Minneapolis

Jeff Root
2009-Sep-06, 08:52 PM
Lemme check this: Betelgeuse is currently rising roughly between 1:30 AM
and 2 AM daylight savings time just about everywhere, right? (For a limited
range of values of "everywhere", of course.)

-- Jeff, in Minneapolis

Tobin Dax
2009-Sep-06, 10:49 PM
Jeff, the post you quoted is from August 4th.

Jeff Root
2009-Sep-07, 12:21 AM
I thought I saw the word "August" somewhere....

Got the year right.

-- Jeff, in Minneapolis

Gigabyte
2009-Sep-24, 05:47 PM
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
2009-Sep-24, 07:06 PM
Can I get in on this action?

Maybe with Trinitree but not with me.

trinitree88
2009-Sep-24, 08:13 PM
Can I get in on this action?

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

Gigabyte
2009-Sep-25, 03:29 AM
First, a question. Do you bet it will go supernova in two years, or that it has already gone supernova and we will see it in two years?

Jens
2009-Sep-25, 04:08 AM
First, a question. Do you bet it will go supernova in two years, or that it has already gone supernova and we will see it in two years?

The first would make the bet a bit pointless, wouldn't it. I guess that's why you're asking, just to make sure there is no escape clause?

Gigabyte
2009-Sep-25, 04:14 AM
If the bet is it will go supernova in two years, that means we will see it 642 years from now. OK, our robot bodies and cybernetic minds will.

If the bet is we will see it in two years, that means it went supernova 638 years ago.

Obviously what is meant is we will see the supernova (which has already occurred) in two years. But, when betting something as important as dinner, one should be sure of the terms.

astromark
2009-Sep-25, 05:22 AM
I would advise you to make your own dinner arrangments... 'Betelgeuse' will put on a most spectacular show. When it does this is of interest to us all. Personally hopping that you are correct and, we will see this nova event before the June 12th 2011 date... and its a teas to imagine the news coverage. Astronomical club memberships will be on the increase. I cant wait. Must I remind you that this could be thousands of years yet...

.

gatorain
2009-Sep-25, 06:01 AM
a couple of days ago, i was looking at Betelgeuse through 2 1/2 inches telescope. it actually too bright for my eye. I cant stand look at it for more than 3 seconds max. Its nothing compare to planet Venus, Jupiter, or Sirius even full moon.

does anyone look at Betelgeuse through their amateur telescope? is it seem so bright to your eye?

astromark
2009-Sep-25, 10:14 AM
Do I need to stay up to check this... ? ;)

My friend, with a 2 and a 1/2 inch scope.. Regardless of the eye piece and magnifacation... If it ( Betelgeuse ) looks brighter than Sirius. Then its happened., or you are looking at a street lamp. :( or had the sun set :)

Please go outside and look at the Orion constalation... and report back. Do it NOW.
@ 15 past 10pm its not in my sky till 3am... England France anybody...

Tog
2009-Sep-25, 12:26 PM
From the parking lot at work, I can see Rigel, Betelgeuse, and the Belt. Betelgeuse doesn't seem any brighter than Procyon. The two look nearly identical to my naked (and nearsighted) eyes. Both are dimmer than Rigel, but brighter than Aldebaran.

Dgennero
2009-Sep-25, 03:32 PM
I can confirm that (brighter than Aldebaran, about like Procyon). I also estimated Betelgeuse yesterday about 0.2 to 0.5 magnitudes brighter than Mars, a good comparison object due to similar color.
Here is the Path of Mars 2009-2010 (http://homepage.ntlworld.com/mjpowell/Astro/Naked-Eye-Planets/Mars-Path-2009-10.htm). Momentarily, Mars should be of magnitude +0.8. That would make Betelgeuse +0.3 to + 0.6 - with a probable observational brightness range for Betelgeuse of +0.3 to +1.2 that is still "in the green", though on the bright side.
It is difficult to compare, say, Betelgeuse and Rigel not only because of the different colors but also because different people are differently sensitive towards the red or blue end of the spectrum. My sister constantly judges blue stars brighter than I do, while for me the reds (Mars, Betelgeuse, Antares, Aldebaran, Garnet star) are striking.
No signs of a supernova yet.

Dgennero
2009-Sep-25, 03:58 PM
@Tog: Let's get to the core of the matter: comparison with other observers: If you enter Alpha Ori into the SBIG light curve generator (http://www.aavso.org/data/lcg/) which is based on observations of variable stars, you'll see that our observations look good - yes it is momentarily in the brighter-than-+0.6 range :)

dgavin
2009-Sep-25, 06:35 PM
@Tog: Let's get to the core of the matter: comparison with other observers: If you enter Alpha Ori into the SBIG light curve generator (http://www.aavso.org/data/lcg/) which is based on observations of variable stars, you'll see that our observations look good - yes it is momentarily in the brighter-than-+0.6 range :)

Thanks for that link, I entered some paramters for Betelgeuse and did a long term plot (about 8 years). http://www.aavso.org/cgi-bin/lcg.pl?auid=Alpha+Ori&lastdays=3600&start=&stop=2455100.2648&obscode=&obscode_symbol=2&visual=on&uband=on&bband=on&v=on&obstotals=on&grid=on&pointsize=1&width=800&height=600&mag1=&mag2=&mean=&button_name=Please+Wait... (http://www.aavso.org/cgi-bin/lcg.pl?auid=Alpha+Ori&lastdays=3600&start=&stop=2455100.2648&obscode=&obscode_symbol=2&visual=on&uband=on&bband=on&v=on&obstotals=on&grid=on&pointsize=1&width=800&height=600&mag1=&mag2=&mean=&button_name=Please+Wait)...

While it's a bit early to tell fo certain, or even guess at reasons for, it seems like there is a noticable, non 6-year cycle, brightening of Betelgeuse.

Albion
2009-Oct-03, 01:30 AM
So, what happens if I happen to be looking at Betelgeuse through a telescope right when it goes supernova?

Gigabyte
2009-Oct-03, 01:46 AM
You go blind. But only in one eye.

Jens
2009-Oct-03, 02:53 AM
You go blind. But only in one eye.

Would you? How long does it take a supernova to achieve peak brightness?

gatorain
2009-Oct-03, 03:57 AM
i'll have to be extra careful when looking at the stars at the night time. u never know if it goes supernova or something, that can be extremely bright like our sun.

chornedsnorkack
2009-Oct-03, 09:29 AM
i'll have to be extra careful when looking at the stars at the night time. u never know if it goes supernova or something, that can be extremely bright like our sun.

Only at an extremely short distance.

Crab was about -6 at 6000 lightyears. It would have to be at a distance of 0,6 lightyears to be as bright as Sun.

Now, a GRB is another matter!

Clarke Burst was +5,4 at 7,5 milliards of lightyears. Which means that it would have been as bright as Sun at 3000 lightyears, not taking account of red shift and geometry of universe.

What is the rise time of a GRB? If Eta Carinae went GRB, would there be time to blink?

Dgennero
2009-Oct-09, 02:09 PM
I think a GRB would hit very suddenly if we're in the line of fire, which we are not concerning Big B.
There's an article claiming Betelgeuse and Antares going supernova (http://www.doomdaily.com/2009/betelgeuse-antares-are-going-supernova/) on the grounds of a sudden higher conversion rate of ni56 and co56 - I am ignorant of that process, so maybe one of you knows more. Woo-woo or not, that's the question.

mantiss
2009-Oct-09, 03:07 PM
I think a GRB would hit very suddenly if we're in the line of fire, which we are not concerning Big B.
There's an article claiming Betelgeuse and Antares going supernova (http://www.doomdaily.com/2009/betelgeuse-antares-are-going-supernova/) on the grounds of a sudden higher conversion rate of ni56 and co56 - I am ignorant of that process, so maybe one of you knows more. Woo-woo or not, that's the question.

How does a GRB hit more swiftly than any other? A GRB either hits or not, every GRB is sudden, just check http://grb.sonoma.edu

I think the only precursor to a SN everyone will agree on is a burst of neutrino. I'm not aware of any other way to predict a SN, and the Neutrino burst would at best be a few milliseconds before the visual light onset.

Finally, just by the name of the website you quote, I would definitely be suspicious of the content, tinfoil hat time methinks. :lol:

StupendousMan
2009-Oct-09, 06:05 PM
I think the only precursor to a SN everyone will agree on is a burst of neutrino. I'm not aware of any other way to predict a SN, and the Neutrino burst would at best be a few milliseconds before the visual light onset.


Not milliseconds, hours.

It takes the shockwave hours to move from the core
to the envelope where we can see it.

mantiss
2009-Oct-09, 07:47 PM
Not milliseconds, hours.

It takes the shockwave hours to move from the core
to the envelope where we can see it.

Very true, thank you for the heads up :)

Kokomala
2009-Oct-24, 02:07 AM
just a quick calculation with facts from the Betelgeuse wiki: wikipedia.org/wiki/Betelgeuse

Betelgeuse radius: 936 x of Sol : 700,000 km x 20 = 650,000,000 km

Betelgeuse rate of shrinking: 210–219 m/s = 19000 km per day

650,000,000/19,000 = 94 years until, well, theoretically, Betelgeuse would be a point.

I'm sure there would be slowing at some point, but the original article says that the shrinkage rate is increasing so far.

If my other posts appear, ignore them as I didn't realize that using an URL would trigger mod approval, and my radius of B was totally wrong, I realized later.

tdvance
2009-Oct-24, 01:23 PM
It looks like all your attempts went through....

antoniseb
2009-Oct-24, 01:27 PM
just a quick calculation with facts from the Betelgeuse wiki: wikipedia.org/wiki/Betelgeuse...

As you seem to have figured out, new members can't post links.

Glom
2009-Oct-24, 02:05 PM
Has it blown up yet?

This shrinkage may just be a convulsion that stars do at the end of their lives before dropping dead.

antoniseb
2009-Oct-24, 04:49 PM
Has it blown up yet? ...

If you mean "Have we seen it blow up?" the answer is no.
If you mean "Did it blow up, and we're waiting the many years till the blast wave gets to us?" the answer is probably not, but who knows.

Dgennero
2009-Oct-24, 08:37 PM
We have yet to see a SN in development. We only know it after the fact, and even the last SN in our galaxy has been hundreds of years ago. One is statistically overdue - which means basically nothing :)

antoniseb
2009-Oct-24, 09:49 PM
... One is statistically overdue - ...

That could be true, or it could be that we've missed a few that went off in or behind thick layers of dust. But, even if it is true, there are a lot of candidates to be next. Betelgeuse is merely one of the close ones.

Hornblower
2009-Oct-24, 10:58 PM
Has it blown up yet?

This shrinkage may just be a convulsion that stars do at the end of their lives before dropping dead.

Or it may be part of the slow, irregular variation that all evolved red supergiants undergo.

Jeff Root
2009-Oct-25, 03:18 AM
If Betelgeuse does blow, would someone please post the news here?
I don't want to miss hearing about it just because I'm not a news junkie.
And if you can't do it yourself, could you arrange for your grandchildren or
great-grandchildren or their great-grandchildren or their great-grandchildren
to post it? Thank you.

-- Jeff, in Minneapolis

Kokomala
2009-Oct-26, 09:48 AM
It looks like all your attempts went through....

Even worse than I thought...

Is the radius of B at least accurate on the wiki site?

EricFD
2009-Oct-26, 03:20 PM
If Betelgeuse does blow, would someone please post the news here?
I don't want to miss hearing about it just because I'm not a news junkie.
And if you can't do it yourself, could you arrange for your grandchildren or
great-grandchildren or their great-grandchildren or their great-grandchildren
to post it? Thank you.

-- Jeff, in Minneapolis

If you want to know beforehand when Betelgeuse goes supernova, if it goes supernova in our lifetimes, then this is where you want to sign-up: http://snews.bnl.gov/. The purpose of SNEWS: SuperNova Early Warning System is to detect the neutrinos that precede a massive star like Betelgeuse going supernova. If you sign-up with SNEWS, they will send you an email alert the moment they detect neutrinos and before the supernova is even visible from Earth. I signed-up with them several years ago, and I'm ready and waiting! :lol:;)

Dgennero
2009-Oct-27, 01:58 PM
OK, I just signed up.
Besides, since my main interest is irregular/semiregular variable stars (though I do no scientific work such as recording light curves), I'll put Betelgeuse on top of my list.
I'll inform you of any sudden change in brightness in excess of 0.5 mag.

Jeff Root
2009-Oct-27, 02:36 PM
Thanks, Eric! That is exactly what I wanted.

And thanks, Dgennero, that is good for me as I don't check my e-mail
every day but I do log on to BAUT practically every day.

Now I'll just sit here and wait for Betelgeuse to do its thing...

-- Jeff, in Minneapolis

Messier Tidy Upper
2009-Oct-27, 03:29 PM
OK, I just signed up.
Besides, since my main interest is irregular/semiregular variable stars (though I do no scientific work such as recording light curves), I'll put Betelgeuse on top of my list.
I'll inform you of any sudden change in brightness in excess of 0.5 mag.

Is it just me or is Betelgeux currently looking brighter than Rigel or at least about equal?

(Could just be me - wouldn't be the first time I've been very much mistaken here.)

Oh & Thanks Dgennero - that'd be much appreciated. :-)

Glom
2009-Oct-28, 07:33 AM
If you want to know beforehand when Betelgeuse goes supernova, if it goes supernova in our lifetimes, then this is where you want to sign-up: http://snews.bnl.gov/. The purpose of SNEWS: SuperNova Early Warning System is to detect the neutrinos that precede a massive star like Betelgeuse going supernova. If you sign-up with SNEWS, they will send you an email alert the moment they detect neutrinos and before the supernova is even visible from Earth. I signed-up with them several years ago, and I'm ready and waiting! :lol:;)

Slight problem with that acronym. It sounds like "snooze", which is what non-geeks will mock it as.

EricFD
2009-Oct-28, 11:49 AM
Slight problem with that acronym. It sounds like "snooze", which is what non-geeks will mock it as.

Yeah, but do we really care what non-geeks think? Personally, I think the acronym is funny, and I'm the one who posted the link! I think the team members who named the project think it's funny too. Scientific work on a professional level can be extremely tedious, boring and very frustrating. A little humor goes a long way to balance that. ;)

Eric

dgavin
2009-Oct-28, 01:46 PM
There was a Gov agency in my home state, that had a really funny acronym based on thier unit and section name.

Bussiness Audits Division, Administrative Support Services aka B.A.D./A.S.S.

No joke, they renamed it rather quickly when someone used the abbreviation in a email sig block lol

EricFD
2009-Oct-28, 02:12 PM
There was a Gov agency in my home state, that had a really funny acronym based on thier unit and section name.

Bussiness Audits Division, Administrative Support Services aka B.A.D./A.S.S.

No joke, they renamed it rather quickly when someone used the abbreviation in a email sig block lol

LOL dgavin! That's hilarious!

Eric

Dgennero
2009-Oct-29, 02:20 PM
@StevoR: Day before yesterday it was cloudy, but yesterday night I could check it out. It isn't easy to compare a red and a blue star, but I'd say Betelgeuse at the moment just misses Rigel in brightness - so I'd say Big Betty is at 0.3 right now; nothing too unusual. I don't think we can actually hype it into supernovaing ;)
That's within the light curve observation of the last 20 days (http://www.aavso.org/cgi-bin/lcg.pl?auid=Alpha+Ori&lastdays=20&start=&stop=2455134.0980&obscode=&obscode_symbol=2&visual=on&uband=on&bband=on&v=on&obstotals=on&grid=on&pointsize=1&width=600&height=450&mag1=&mag2=&mean=&vmean=&button_name=Please+Wait...).

dgavin
2011-Aug-18, 09:07 PM
Recent light curve plots show that's it's slowly increasing in brightness over the last two years, the upper end of the mag. heading into the negatives. No idea what this means.

Plot attached (1080HD res)

15329

Jeff Root
2011-Aug-18, 10:02 PM
Any idea why the green dots so often make a line descending
over the course of a year's observations? And why, in contrast,
two years near the end of the graph have the green dots
scattered all over?

-- Jeff, in Minneapolis

Tensor
2011-Aug-19, 12:26 AM
Recent light curve plots show that's it's slowly increasing in brightness over the last two years, the upper end of the mag. heading into the negatives. No idea what this means.

Plot attached (1080HD res)

15329

Any idea why the photometric observations in the B and U bands have stopped? I would think that if the visual indicated an increase in brightness, that there may be an increase in the magnitude of the blue band.

dgavin
2011-Aug-19, 07:12 PM
Jeff, my only guess is that as it's in the green bands, is it's somethign to do with seasonal atmosperic absorbtion in the green bands. I can;t think what else might cause that sort of odd reading in one specifc band.

dgavin
2011-Aug-19, 07:15 PM
Any idea why the photometric observations in the B and U bands have stopped? I would think that if the visual indicated an increase in brightness, that there may be an increase in the magnitude of the blue band.

No, no idea on that. I agree with you that it would seem the blue band should be looked at more, when there is an indication of mag. increacing.

Glom
2011-Aug-19, 10:21 PM
So has it begun?

Or could this just be a convulsion? Would a star like Betelgeuse have convulsions?

dgavin
2011-Aug-20, 01:35 AM
So has it begun?

Or could this just be a convulsion? Would a star like Betelgeuse have convulsions?

It's an odd star that appears to have three cycles of variences normaly. A three time a year one, mostly in the greeen spectrum. A yearly one, in the visible, and then the every six year one which arrearch to be time of less magnitude. This increase of magnitude is just occurign after one of those time of less magnitude so it might just be a brighter then normal rebound after it's six year contraction pulse. Thats my best guess on it though.

Van Rijn
2011-Aug-20, 01:35 AM
So has it begun?

Or could this just be a convulsion? Would a star like Betelgeuse have convulsions?

If you're asking if the supernova will be soon, nobody knows. Don't get your hopes up, though.

dgavin
2011-Dec-08, 08:18 PM
Checked the light curves on http://www.aavso.org/ today and it appears to be decresing in magnitude over the last few months instead of the increasing trend over the last 2 years. I'm not sure if this has any bearing on it shrinking or not, but i suspect it might mean a slowdown in the rate of shrinkage of the star.

PraedSt
2011-Dec-08, 09:13 PM
Checked the light curves on http://www.aavso.org/ today and it appears to be decresing in magnitude over the last few months instead of the increasing trend over the last 2 years. I'm not sure if this has any bearing on it shrinking or not, but i suspect it might mean a slowdown in the rate of shrinkage of the star.I don't think there been any supernova candidates that we've subsequently seen exploding, have there? I was trying to find a light curve on that site to compare with Betelgeuse. No joy.

glappkaeft
2011-Dec-09, 12:11 AM
I don't think there been any supernova candidates that we've subsequently seen exploding, have there? I was trying to find a light curve on that site to compare with Betelgeuse. No joy.

The most recent supernova in the Milkyway was observed in 1604 and thus predates modern measurments by a few centuries. SN1987a in the Large Magellenic Cloud is usually identified with Sanduleak -69° 202 but I doubt good studies of that star had been made prior to the event. Might not hurt to check though.

PraedSt
2011-Dec-09, 06:03 AM
The most recent supernova in the Milkyway was observed in 1604 and thus predates modern measurments by a few centuries. SN1987a in the Large Magellenic Cloud is usually identified with Sanduleak -69° 202 but I doubt good studies of that star had been made prior to the event. Might not hurt to check though.With all the recent SN discoveries I'd forgotten that small fact :doh:
I couldn't find a pre-explosion light curve for Sanduleak -69° 202, but I did find some interesting curves for candidates. Like Eta Car for example. http://www.aavso.org/lcg/plot?auid=000-BBR-655&starname=ETA%20CAR&lastdays=8000&start=&stop=2455904.7492040163&obscode=&obscode_symbol=2&obstotals=yes&calendar=calendar&forcetics=&grid=on&visual=on&pointsize=1&width=600&height=450&mag1=&mag2=&mean=&vmean=

glappkaeft
2011-Dec-09, 06:13 AM
With all the recent SN discoveries I'd forgotten that small fact :doh:
I couldn't find a pre-explosion light curve for Sanduleak -69° 202, but I did find some interesting curves for candidates. Like Eta Car for example. http://www.aavso.org/lcg/plot?auid=000-BBR-655&starname=ETA%20CAR&lastdays=8000&start=&stop=2455904.7492040163&obscode=&obscode_symbol=2&obstotals=yes&calendar=calendar&forcetics=&grid=on&visual=on&pointsize=1&width=600&height=450&mag1=&mag2=&mean=&vmean=

Yeah, but the problem with the candidates is that we are pretty sure it's likely that they will not blow up for thousands if not millions of years. The next visible (and overdue) supernova in the milky way will most likely be one of the stars further away, and mostly obscured by dust, than the easily observed candidates. Supernovas are if nothing else bright and will pierce the dust while most concurrent studies won't. We'll just have to hope that radio and IR studies in the dust windows will give enough insight when she blows...

trinitree88
2011-Dec-09, 01:44 PM
The most recent supernova in the Milkyway was observed in 1604 and thus predates modern measurments by a few centuries. SN1987a in the Large Magellenic Cloud is usually identified with Sanduleak -69° 202 but I doubt good studies of that star had been made prior to the event. Might not hurt to check though.

The most recent supernova in the Milky Way was ~ 140 years ago SEE:http://science.nasa.gov/science-news/science-at-nasa/2008/14may_galactichunt/

Hornblower
2011-Dec-09, 02:44 PM
I don't think there been any supernova candidates that we've subsequently seen exploding, have there? I was trying to find a light curve on that site to compare with Betelgeuse. No joy.

Are you suggesting that there might be something about the light curve that is indicative of whether or not it is about to blow? If so, what do you think we should look for?

glappkaeft
2011-Dec-09, 04:13 PM
The most recent supernova in the Milky Way was ~ 140 years ago SEE:http://science.nasa.gov/science-news/science-at-nasa/2008/14may_galactichunt/

Yes, but that supernova (and others) wasn't observed at the time, astronomers detected the remnant, so they are useless for this purpose. There have probably been a few more supernovas since then that have been missed entirely so far.

jfribrg
2011-Dec-09, 06:19 PM
If this event happened today, would our current technologies detect it as it happened? For instance, would we detect the neutrino burst or would some radio or x-ray telescope sky survey detect it automatically, or would we need someone to serendipidously happen to be looking at the correct part of the sky ?

glappkaeft
2011-Dec-09, 09:22 PM
If this event happened today, would our current technologies detect it as it happened? For instance, would we detect the neutrino burst or would some radio or x-ray telescope sky survey detect it automatically, or would we need someone to serendipidously happen to be looking at the correct part of the sky ?

Swift is built to detect nearby supernovas among other things but can't cover the entire sky. The Supernova Early Warning System (SNEWS) uses neutrino detectors to give heads up that a supernova is occurring, in fact it would detects it even before we can see the light, but can't give directional data. I could not find any extinction data for G1.9+0.3 (but lots of "woo" - any search phrases with "G1.9+0.3" + extinction results in mountains of it) but in the direction of the milky way core extinction can be up to 30 magnitudes (about 1 photon out of one trillion get through) in visual light. This would dim even a very bright SN to the equivalent of absolute magnitude of around +10. At 25'000 LY this would be only an apparent magnitude of +24.4. While this is detectable it's very hard to spot a new 24.4 magnitude "star" and I doubt that good measurements can be taken with such a weak signal. In this case one would have to hope that Swift pinpoints the location so that the SN can be studied in radio/IR and X-Ray wavelengths

PraedSt
2011-Dec-09, 10:09 PM
Are you suggesting that there might be something about the light curve that is indicative of whether or not it is about to blow? If so, what do you think we should look for?I was hoping :)

But here's a curve of a recurrent nova, RS Oph:
http://www.aavso.org/lcg/plot?auid=000-BBZ-452&starname=RS%20OPH&lastdays=&start=2451200&stop=2454400&obscode=&obscode_symbol=2&obstotals=no&calendar=JD&forcetics=&grid=on&visual=on&pointsize=1&width=600&height=450&mag1=&mag2=&mean=&vmean=
Unfortunately there doesn't seem to be anything there that's an obvious sign of impending change.

dgavin
2012-May-02, 07:08 PM
Updated light curves for Betelguese.

AAVSO.ORG light curve generator (http://www.aavso.org/lcg/plot?auid=000-BBK-383&starname=BETELGEUSE&lastdays=8000&start=&stop=2456050.28542&obscode=&obscode_symbol=2&obstotals=yes&calendar=calendar&forcetics=&grid=on&visual=on&uband=on&bband=on&v=on&pointsize=1&width=800&height=450&mag1=&mag2=&mean=&vmean=)

It looks to have started this group of mesurments back at previous levels, but them jumped back up to its almost brightest level again. While it doesn't look any more likely to blow up yet, it does appear that it may be developing some new variabilitiy.

Glom
2012-May-11, 01:26 PM
Would these be the convulsions?

dgavin
2012-May-14, 06:38 PM
It's possible, but I think a few more years of light curves would be needed to make any sort of educated determination.