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By rs1 on 7/22/2010 3:33:54 PM , Rating: 2
This article seems to be essentially a trimmed-down version of the story that CNN posted yesterday:

There's nothing wrong with reposting news articles from other sites, per se, but how about at least adding a few of your own contributions? For instance, I'd be interested in the science behind how this star manages to avoid collapsing in on itself and becoming a black hole. It's certainly massive enough to do so, so why doesn't it?

RE: Copy
By Josett on 7/22/2010 11:55:54 PM , Rating: 2
A good point, at last.

Mainly because electromagnetic repulsion (fusing Hydrogen atoms into Helium ones) still overcomes its gravitational pull. Within some few hundreds of thousands of years (perhaps less; I didn't make the calculations), it most probably will become a black-hole.

Simplistically, and to get it into perspective, the assumed initial minimum for a star-like object to collapse into a b-h, is about 2,5 solar masses. This one was about 320.


RE: Copy
By Executor115 on 7/24/2010 10:01:49 AM , Rating: 2
A star this massive almost certainly will not form a black hole. Above about 130 solar masses, a dying star will undergo a pair-instability supernova instead of a core-collapse one that lower mass stars undergo and which produce neutron stars and black holes. A pair-instability supernova occurs when a star's core grows so hot that it beings producing photons with energies greater then the mass of an electron-positron pair. While the pair will usually annihilate each other and release another photon in a random direction, when this is happening the photon is basically stopped and not helping the star against gravity. A star depends on photon pressure to keep it in hydrostatic equilibrium with gravity. As the temperature increases, more high-energy photons are created, but the distance each one travels before some kind of interaction is actually decreasing. For a few seconds, the star collapses, fusing its entire core, but the huge release of thermal energy is far more then the gravitational binding energy, so the star simply explodes without leaving anything behind.

RE: Copy
Good point.

Had to Wiki it but anyway...

250 solar masses or more


Thanks for the pertinent post.


