Betelgeuse

[Gamefreak89]

Hey I'm just wondering if the B star Betelgeuse where to or has already gone supernova and it reaches Earth within the next few years or less what would the effects be? Is the star a threat to us or just something else?

[Gamefreak89]

Hmm... well anyways can anyone tell me anything about Betelgeuse just wonderin is it a threat if it did go supernova a while ago and yet to reach the Earth.

[Spoons]

Ok then I'm just wondering though... lol because I just posted another thread about the star betelgeuse lol.

Found something else to be scared of then? Kidding - I'm just kidding with you. I hope you're not freaking about that though... I'll go look.

ETA:
My understanding is that Betelgeuse would be a scientifically interesting occurrence, but not significantly dangerous. I'd need to look that up though, I may have stars mixed up. I thought the idea was that it's really only supernovas with GRBs etc which have their poles aimed directly at us, which given 3 dimensional geometry is extremely rare for anything close enough to cause significant trouble.

Someone can probably correct me at least alittle there though.

[Gamefreak89]

No just a little concerned though because a friend of mine told me about the star.

[Spoons]

Ok, see this site.

http://space.wikia.com/wiki/Betelgeuse

It's actually probably a reasonable source of info for a number of your questions.

There is a consensus that such a supernova would be a spectacular astronomical event, but would not — being so distant — represent any significant threat to life on Earth.

[Spoons]

Regarding the timeframe for the supernova, on that site I linked, they had this to say:

Curiously, 1st century BC Chinese records unearthed by Shu-ren, Jianmin and Jin-Yi in 1980 refer to the color of Betelgeuse as being white or yellow. However, Ptolemy writing in 150 AD calls it a red star. Therefore, Fang Lizhi, a Chinese astrophysicist, proposed that Betelgeuse could have turned into a red giant star during that period. It is known that as stars use up the hydrogen fuel in their cores, their color changes from white to yellow to red. Shu-ren et al. suggest that Betelgeuse could have changed its color when it expelled a shell of dust and gas, that, even now, can be seen to be expanding away from it. Thus, if their theory is right, it is unlikely that Betelgeuse will become a supernova any time soon because a star usually stays a red giant for tens of thousands of years.

The suggestion is that it should have quite a while to go before going supernova.

[Gamefreak89]

Ok so if it already went supernova a while ago what will happen to a few years or less what would the effects be, is it a gamma ray star, how close would it have to be considered dangerous?

[Gamefreak89]

How can you tell if its not a gamma ray star like a wolf-rayet star and the distance considered in it?

[Spoons]

The major risk, as I understand is from the gamma rays which burst out in lines along the axis. Even then, I don't think you read tha link I provided you very well...

However, if Betelgeuse's axis (one of its poles) is pointed towards Earth there would be tangible effects here. A shower of gamma rays and other cosmic particles would be directed at Earth. There would be spectacular aurorae and possibly a measurable diminution of the ozone layer with consequent adverse radiation effects on life.

Before you go worrying over things like this you really should do a little research - you could ease a lot of your stress that way.

[Gamefreak89]

So meaning that even if it was pointing at us it won't do much damage to us am I correct?

[Jens]

Hey I'm just wondering if the B star Betelgeuse where to or has already gone supernova and it reaches Earth within the next few years or less what would the effects be? Is the star a threat to us or just something else?

No, it's not. It will be a pretty sight, that's all.

[Spoons]

Well, generally. There is a particular radius, which I think is based on the size of the star & thus supernova explosion, and possibly due to the composition of the star, within which it would be major trouble, but I do not believe we are within that radius.

It seems quite certain from the linked article that this is the case. I'm mostly just praphrasing that at this point. Are you sure you've read it?

[Gamefreak89]

Well I did read it and was just wondering if a possible gamma ray hits part of the Earth's ozone how much damage it could do.

[Gamefreak89]

Hmm.. I wonder how long the light show will last in the sky?

[Swift]

To keep it all neat and tidy, I've moved the Betelgeuse posts from the killer asteroid thread to this one.

The most important thing in any impending doomsday is to keep things well organized (I'm making a joke).

[Strange]

There was a recent thread on this subject: http://www.bautforum.com/showthread....ous-supernovae

Someone even posted a comprehensive list of all the potentially dangerous supernova candidates (see post #2 of that thread)

ETA:

The most important thing in any impending doomsday is to keep things well organized (I'm making a joke).

I don't think that keeping things properly organized is any joking matter!

[Gamefreak89]

Hey has anyone seen the mega disaster episode about how humans surviving a gamma ray burst its pretty interesting someone ought to give it a try.

[chornedsnorkack]

Hmm.. I wonder how long the light show will last in the sky?

Till when?

How long does a supernova lightcurve take to reach the luminosity of the original star? And a supernova remnant at first magnitude would still be "light show"...

[Gamefreak89]

Well I know 2 things humans can survive a gamma ray burst and a the light show from the star betelgeuse lasts about 6 months I believe so but then again I'm not very sure...

[Jens]

How long does a supernova lightcurve take to reach the luminosity of the original star? And a supernova remnant at first magnitude would still be "light show"...

I'm thinking a couple of months, but that could be off a bit. Also, IIRC the remnant will fade to become much less brighter than the original star, won't it? The star is no longer shining (since it is no longer with us) so the gas will gradually fade and fade and fade, I think.

[chornedsnorkack]

I'm thinking a couple of months, but that could be off a bit. Also, IIRC the remnant will fade to become much less brighter than the original star, won't it? The star is no longer shining (since it is no longer with us) so the gas will gradually fade and fade and fade, I think.

How much less brighter?

Crab, at about 6000 lightyears from us, is magnitude 8,4, near 1000 years after explosion.

Betelgeuse, at about 600 lightyears, is about 10 times closer and thus 5 magnitudes brighter.

In 1000 years, the remnant of Betelgeuse would be magnitude 3,4. Easily visible for naked eye - brighter than Praesepe or 47 Tucanae or Orion or Andromeda Nebula.

What would a supernova look like, that slowly and gradually expands from a point star into an unmistakably extended object over decades and centuries, being naked eye visible and prominent all the while?

1000 years after explosion, Crab pulsar at Betelgeuse´s distance would be dim at magnitude 11. But how bright would a pulsar be 100 years after explosion? Would it shine through the gas cloud in 10 years?

[Glom]

Hey I'm just wondering if the B star Betelgeuse where to or has already gone supernova and it reaches Earth within the next few years or less what would the effects be? Is the star a threat to us or just something else?

Betelgeuse isn't a B type star. It's in the M range. Being a red supergiant, means it has a cool surface. There's just a hell of a lot of surface so it totals up to a great luminosity.

People have been promising Betelgeuse will go supernova for months now. I'm getting impatient.

[Gamefreak89]

LOL but I am right about the mega disaster episode of gamma ray bursts right?

[Dgennero]

AFAIK, GRBs burst out of the poles like beacons. Since we aren't looking at one of Betelgeuse's poles, we aren't in the line of sight and won't be hit.
The supernova will look like this in the sky.
Last year, the shrinking of Betelgeuse was in the media which boosted speculations about a demise soon.
But "soon" on a cosmic scale isn't soon on a human scale. If the shrinking continues and *if* there should be a violent rebound, it could still take decades to such a rebound at this rate (15% since 1993), which could also just be part of a longterm cyclical event that we are just beginning to notice.
Don't hold your breath.

[Gamefreak89]

Oh I see I was looking forward to one though...

[EDG]

I tried to figure out what a supernova would look like close up, and the thing that kinda blows my mind is that (from our viewpoint) the supernova wouldn't happen everywhere on the star at once. Because red supergiants like Betelgeuse are so huge (several AU across), there'd actually be a delay since the light from the limb of the star would take a lot longer to get to our eyes than the light from the point on the star closest to us (since it's several AU away from us). I figured you'd see a brain-searingly bright point of light appear below you on the star, which would expand into a disc that expanded at lightspeed across the stellar surface til it consumed the whole thing.

Would that be accurate, or am I missing something?

[Cruithne3753]

I tried to figure out what a supernova would look like close up, and the thing that kinda blows my mind is that (from our viewpoint) the supernova wouldn't happen everywhere on the star at once. Because red supergiants like Betelgeuse are so huge (several AU across), there'd actually be a delay since the light from the limb of the star would take a lot longer to get to our eyes than the light from the point on the star closest to us (since it's several AU away from us). I figured you'd see a brain-searingly bright point of light appear below you on the star, which would expand into a disc that expanded at lightspeed across the stellar surface til it consumed the whole thing.

Would that be accurate, or am I missing something?

Remember, even though its bulk might be thinly extended over a number of AU, the majority of the mass is concentrated in the core, probably similar in size to the Sun. (but not the Sun's core of course! Someone correct me if I'm wrong) The outer layers won't be involved directly in the SN explosion itself other than getting blown off.

[EDG]

Remember, even though its bulk might be thinly extended over a number of AU, the majority of the mass is concentrated in the core, probably similar in size to the Sun. (but not the Sun's core of course! Someone correct me if I'm wrong) The outer layers won't be involved directly in the SN explosion itself other than getting blown off.

Yeah, that's what I'm talking about here though. The insides will collapse, but (a) it'll take a while for the explosion/shockwave to break through the surface of the star and (b) when it does, we'll see the closest parts of the star to us brighten first, and then that will spread across the star's surface.

Put it this way, a pulse of radiation travelling outward from the core at lightspeed would still take about 40 minutes to hit the surface of a 5 AU radius red supergiant!

[slang]

Yes. Before I knew this, I saw a couple of "events" in the sky, thinking that just maybe they might be a supernova. Now, having read up a bit, I know that I most likely saw reflections of spacecraft, or meteors at a steep angle. Because supernovas are not seconds type events. Still, it was fun to hit astronomy news sites the next day to check.

[Gamefreak89]

Sounds intriguing.