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I've heard that very massive stars can sometimes collapse into black holes without creating supernovae.

How does this happen?

(I suspect it's something to do with the relative lack of Urca process neutrinos which are active in the cooling of neutron stars).

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The formation of a supernova requires the collapsing core of the star to be arrested by a combination of neutron degeneracy pressure and (mainly) the strong nuclear force repulsion between closely packed neutrons. The halt of the collapse drives a shock outwards (the core bounce). In numerical models, the shock stalls but it may be re-energised by absorbing some of the copious neutrinos that are produced in URCA-like processes and neutrino bremsstrahlung in the central proto-neutron star. It is the deposition of some tiny fraction of the neutrino energy that ultimately drives the supernova.

If the collapsing core is too massive, then the collapse may not be halted in the first place. Alternatively, it may be that the neutrinos manage to escape without depositing enough of their energy into the stellar envelope to make it explode. This is more likely to happen in more massive stars simply because a larger amount of deposited energy is needed to drive the explosion. Either would result in a black hole but no supernova. See for example the discussions in Fryer (1999) and the introduction of Reynolds et al. (2015).

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I think if a star when its death life cycle starts and it began to collapse under its own gravity so if the core is so massive say above or equal to 30 times the mass of sun than it may not generate enough pressure to counteract the gravity and may not go to supernova and collapses to black hole.

Hope it helps.

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  • $\begingroup$ This does not provide an answer to the question. Once you have sufficient reputation you will be able to comment on any post; instead, provide answers that don't require clarification from the asker. - From Review $\endgroup$
    – Miyase
    Oct 2, 2023 at 16:22
  • $\begingroup$ @Miyase this does provide an answer, it is just wrong. $\endgroup$
    – Kyle Kanos
    Oct 2, 2023 at 20:25
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    $\begingroup$ @KyleKanos The automated message contains "that don't require clarification from the asker", which I think is spot-on with this answer. Not only is it largely wrong, it's also very unclear and provides no reference to validate its content. $\endgroup$
    – Miyase
    Oct 2, 2023 at 20:57
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    $\begingroup$ What is unclear about the assertion that $30M_\odot$ is a point in which gravitational collapse exceeds the pressure? Sure it's wrong, but unclear? I'm not convinced. And since when have we ever needed references for answers on PSE? $\endgroup$
    – Kyle Kanos
    Oct 3, 2023 at 1:53

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