Star collapse to form directly a black hole

[shounakbhatta]

Hello,

Does a star collapse directly to form a black hole without creating a supernova or whether a supernova forms some neutron stars which after crossing the TOV limit forms a black hole?

Thanks.

 

[Simon Bridge]

Nobody knows.
It seems unlikely that a body massive enough to form a black hole will not also pass through an explosive stage, maybe a supernova, by much the same mechanism as the formation of neutron stars. We know that supernovae leave behind very collapsed objects but we do not know that all collapsed objects form from supernovae.

For instance, it may be possible for a black hole to form by cannibalism of close stars by a big one. In that case, matter gets added gradually. But you'd still think the big final collapse would release a lot of energy in one go.

There's also supermassive and primordial black holes ... the area is quite open.

 

[Chronos]

It is generally believed that very massive stars can skip the whole supernova thing and directly collapse into a black hole - http://iopscience.iop.org/0004-637X/522/1/413/fulltext/40269.text.html

 

[Simon Bridge]

Oh cool! Reading material <reads> thanks...

 

[pmacias]

I can tell you that the process of a star collapsing to form a black hole is complex and there are still many unknowns. It is believed that for a star to collapse directly into a black hole, it must have a mass greater than about 20 times the mass of our sun. In this case, the gravitational forces are strong enough to overcome the outward pressure caused by nuclear fusion, causing the star to collapse directly into a black hole. However, for stars with masses lower than this, it is believed that a supernova explosion occurs first, which can either result in a neutron star or a black hole depending on the mass of the star. The exact mechanisms and conditions for the formation of black holes are still being studied and researched by scientists. So, to answer your question, it is possible for a star to collapse directly into a black hole, but it may also go through a supernova stage first.