PDA

View Full Version : Energy of Supernovae

Tom Mazanec
2012-Jan-17, 02:19 PM
What is the energy output of:
1) A type Ia supernova
2) A type II supernova
3) A pair production supernova
4) Any other models I have forgotten?
And just for fun, lets denominate it in megatons :)

antoniseb
2012-Jan-17, 02:58 PM
... And just for fun, lets denominate it in megatons :)

There are 4x1022 ergs per megaton.
Type II are about 1053 ergs
Type 1a are about 1051 ergs
Pair Instability --- about 1054 ergs (not many well observed examples)

After you do the division and get megatons, you'll still have a number too big to discuss cogently. If the whole Earth were suddenly turned into U235, the explosion would sill be much smaller than any of these, so I don't see what converting to megatons gets you.

Tom Mazanec
2012-Jan-17, 03:32 PM
It gets me the fun :)
EDIT: OK, nobody took me up on this, so I guess I will have to do it myself:
I'll use pair-production, since that is the biggest. However, I will conservatively lower the energy to 4X10^53 ergs because of the observational uncertainties. I will also assume that a one megaton H-Bomb can be fit in a sphere one meter in diameter. That means you would need 10^31 H-bombs to make one pair production ersatz pp supernova, which would make up a ball just over 2X10^10 meters on diameter, or a sphere 20 million kilometers in diameter...about half the size of Arcturus or almost big enough to fill the orbit of Jupiter's Himalia group of moons (if I did not make a goof). Or one million Hbombs a second from the Big Bang would get you about 4X10^23 explosions, or four millionths of one percent of the way (again, if I did not goof).
See, I think I discussed this cogently!

astromark
2012-Jan-17, 06:56 PM

The fact is I do not have the slightest interest in grasping the megadeath. ( mega tone ), output of any Star's Nova Event..

but feel I can contribute in a meaningful way...

Rather than know the output of energies in what moment length and velocities..? I have a slightly different query.

That may well require the sort of mathematics I do not grasp well... :)that you might.

How far away is, or must I be, to be safe.. and ly measures will do...

It's the blunt end of your question that might one day kill off humanity..

Tom Mazanec
2012-Jan-17, 07:12 PM
IIRC, 50 LY from a supernova is enough to have a Mass Extinction. For Type IIs, even a few AU, IIRC, will be lethal for JUST NEUTRINOS.

astromark
2012-Jan-17, 09:06 PM
Whooo boy, back up the stage coach.. what is 11RC or is that IIRC ? . . .

I understood type 1 a, and even type 11's...( two's).. just consider that we are not all so savvied.

pzkpfw
2012-Jan-17, 09:27 PM
(If I Recall Correctly)

jfribrg
2012-Jan-18, 12:23 AM
Instead of megatons, maybe you can use the Richter Scale, which is both open-ended and logarithmic. I did a back-of-the-envelope calculation once and concluded that a gamma ray burst has the energy equivalent of a magnitude 34 earthquake. Of course you wouldn't get anywhere near that much energy even if you converted the entire Earth into pure energy ( in which case there wouldn't be any earth left to quake).