Betelgeuse supernova

[Scott]

What's your first?

It would be a shame if ol' Betel explodes; surely, having it around for a while is worth more than a short post-supernova spectacular?

nup, i wanna see it

Scott

[athel]

Well, a few calculations on this...Type II supernova at 640 light years giving 10^46 Joules during a 10 second core collapse is 10^45 Watts. This is radiation at all wavelengths similar to that from a nuclear bomb. A negligible one per cent creates the neutrino driven Baryon expansion, the rest of the energy flashes out into free space and the intensity on a sphere at a given radius can be calculated.

The intensity at the Earth is 2.5*10^6 Watts per sq.m. for 10 seconds. Maybe as much as one half will be thermal radiation. An online figure quoted for the ignition of e.g. dry vegetation for the initiation of fires after a nuclear weapon explosion was 125 Joules per sq.cm. It looks like we may get ten times the dose needed to start fires across much of the land mass. Needless to say we would not want to be observing this event so the best place to avoid the thermal radiation is at the USA base on the south pole. I always wondered why they had so many people down there! They could well be wasting their time though. I have no information on the effects of the massive doses of gamma radiation which will pass through the Earth shield and there may be significant refraction of the thermal radiation over the polar horizon. Well, this is my brief analysis and I am not an expert on supernovae. I just wonder how much warning we may get?

[IanL]

Well, a few calculations on this...Type II supernova at 640 light years giving 10^46 Joules during a 10 second core collapse is 10^45 Watts. This is radiation at all wavelengths similar to that from a nuclear bomb. A negligible one per cent creates the neutrino driven Baryon expansion, the rest of the energy flashes out into free space and the intensity on a sphere at a given radius can be calculated.

The intensity at the Earth is 2.5*10^6 Watts per sq.m. for 10 seconds. Maybe as much as one half will be thermal radiation. An online figure quoted for the ignition of e.g. dry vegetation for the initiation of fires after a nuclear weapon explosion was 125 Joules per sq.cm. It looks like we may get ten times the dose needed to start fires across much of the land mass. Needless to say we would not want to be observing this event so the best place to avoid the thermal radiation is at the USA base on the south pole. I always wondered why they had so many people down there! They could well be wasting their time though. I have no information on the effects of the massive doses of gamma radiation which will pass through the Earth shield and there may be significant refraction of the thermal radiation over the polar horizon. Well, this is my brief analysis and I am not an expert on supernovae. I just wonder how much warning we may get?

Can you set out your calculations in a bit more detail? The assertion that the energy from a type II supernova at 640 light years distance would set fire to vegetation on the Earth's surface, insta-gamma-ray barbecue, etc. doesn't seem right to me. E.g. We've already calculated (and shown our workings) that the visible light component of Betelgeuse going supernova would be similar to that of the full Moon, albeit more dazzling due to being a point source rather than spread over half a degree.

Thus the amount of radiation at other wavelengths must follow the same rule in terms of intensity drop-off with distance. So light and any other forms of radiation would be far less intense than the noon-day sun at the equator, and vegetation there doesn't spontaneously combust as a result of being out in the Sun. I suspect that your maths is faulty but it would be good to understand why (or have you prove your point if you are right.)

From what I have read, a type II supernova at 100 light years distance would pose no threat to life on Earth, but one at a distance of about 50 light years would have some seriously bad effects (like destroying the ozone layer). So at 640 light years, we aren't going to be in any danger.

[IanL]

Actually, here is an interesting article about how a supernova could affect life on Earth:

http://www.space.com/4814-risk-earth-supernova-explosions.html

Basically the upshot is that if it was close enough, or one of the rare 'super luminous' types of supernovae at a greater distance, prolonged exposure to the additional blue light (for maybe six months) during periods when it should be dark could seriously disrupt the biological rhythms of mammals, and thus disrupt ecosystems in unexpected ways (at least in the short term).

[Robstargazer15]

Well lets say Betelguses last rites

RIP Betelguse

born: long time ago

died: in a terrible explosion

[michael.h.f.wilkinson]

Well, a few calculations on this...Type II supernova at 640 light years giving 10^46 Joules during a 10 second core collapse is 10^45 Watts. This is radiation at all wavelengths similar to that from a nuclear bomb. A negligible one per cent creates the neutrino driven Baryon expansion, the rest of the energy flashes out into free space and the intensity on a sphere at a given radius can be calculated.

The intensity at the Earth is 2.5*10^6 Watts per sq.m. for 10 seconds. Maybe as much as one half will be thermal radiation. An online figure quoted for the ignition of e.g. dry vegetation for the initiation of fires after a nuclear weapon explosion was 125 Joules per sq.cm. It looks like we may get ten times the dose needed to start fires across much of the land mass. Needless to say we would not want to be observing this event so the best place to avoid the thermal radiation is at the USA base on the south pole. I always wondered why they had so many people down there! They could well be wasting their time though. I have no information on the effects of the massive doses of gamma radiation which will pass through the Earth shield and there may be significant refraction of the thermal radiation over the polar horizon. Well, this is my brief analysis and I am not an expert on supernovae. I just wonder how much warning we may get?

I do not think this is quit right. I think that much of the light generated is slowed by the outer layers and this dims the peak considerably. Only when the outer layers have thinned sufficiently do they transmit the light from the core. It ultimately does escape. Lets put it another way: Type II supernovae can reach peak luminosities of 10¹⁰ times that of the sun, or 25 magnitudes brighter. That means they have an absolute peak magnitude of about -20. At 10 parsecs that would be 6.74 magnitudes or 500 times fainter than the sun. At 197 parsecs, the supernova would be 388x or 6.47 magnitudes fainter still, giving an estimated brightness of -13.5, or thereabouts. Brighter than the full moon, but nothing is going to catch fire. To be as bright as the sun in the sky, the SN would need to explode at about half a parsec, and nothing is that close.

[stem1989]

would be gutting if it did go in like July for the UK we'd only get daytime views but then again that would still be cool...

[michael.h.f.wilkinson]

would be gutting if it did go in like July for the UK we'd only get daytime views but then again that would still be cool...

If it goes in July, rest assured, it will be cloudy in the UK (and the Netherlands).

[stem1989]

it would be awesome if one night you where just looking up through your scope at betelgeuse and boom it went lol

[tigger]

I think the biggest effect on earth will be on the sale of telescopes-so I suggest you buy all the gear your ever likely to need now and beat the rush.Oh and don't forget the camera,you'll want to show pictures to your grandkids!!! If only I could get my wife to read this topic Cheers Philip

[Stargazing_Cliff]

Be great to witness the big event.

[ollypenrice]

We maybe shouldn't call supernovae 'terrible' explosions. They synthesize most of the elements from which we and our environment are made...

(In Smolin's hypothesis they might even have seeded the universe in which we live...)

Olly

Edited January 24, 2013 by ollypenrice

[SnakeyJ]

Obviously the odds are stacked against any of us witnessing the death of Bettelgeuse, but found a great image of the star and its ejected dust rings taken by Herschel on the Register this morning - http://www.theregist...llision_course/

With a mere 5000yrs estimated until the bow shock collides with the dust fillament, it may offer a few visual treats before its final hurrah!

Edited January 24, 2013 by SnakeyJ

[abovetheroof]

I havnt seen stargazing live (ever) but people in my office have been quizing me about this, i honestly do not believe that it will bright enough to light up the sky.. Plus it may not happen for many many years...

And like said above i like it where it is

you guys might find this interesting, its the last naked eye supernova recording

http://en.wikipedia.org/wiki/SN_1604

...WALKING

[andrew s]

For those interested in what seems to have happened as opposed to the hopes of the press here is an interesting paper from Emily Levesque and Phil Massey https://arxiv.org/abs/2002.10463 who propose " ...that episodic mass loss and an increase in the amount of large-grain circumstellar dust along our sightline to Betelgeuse is the most likely explanation for its recent photometric evolution"

Regards Andrew.

[Marvin Jenkins]

I note with interest in parts of this thread for Orion as we see it to remain the same, the loss of one of the stars to be a great loss to us all. Everything in the universe is in a constant state of change, creation and decay.

M42 in Orions scabbard? A birth place of new stars from a cloud of gas that people outside of astronomy think is a single star. I have to confess I know nothing about M42 origins, but is it not a remnant from a past supernova?
 

I may be wrong but can you imagine what Orion looked like with an extra Red Super  Giant n the scabbard. If it is a super nova remnant can you imagine what it looked like five years after. I am blown away now.

Marv