When an iron core is formed in a massive star, what ultimately keeps the core from collapsing to form a black hole?

Question

Quizplus · Accepted Answer

Neutron degeneracy pressure, which arises due to the Pauli exclusion principle preventing neutrons from occupying the same quantum state, provides the support against gravitational collapse in the core of a massive star after it has gone through successive stages of fusion ending in the formation of iron. When the iron core collapses, it can lead to a supernova explosion, and the remnant can be supported against further collapse by neutron degeneracy pressure, forming a neutron star. If the mass of the remnant exceeds the Tolman–Oppenheimer–Volkoff limit, neutron degeneracy pressure will not be sufficient to prevent collapse to a black hole.

When an Iron Core Is Formed in a Massive Star