Final answer:
The final core collapse leading to a supernova ends when neutron degeneracy pressure halts the collapse and causes the core to rebound, resulting in a shock wave that blows the star apart. This process results in the formation of a neutron star, or, for even more massive cores, a black hole.
Step-by-step explanation:
The final core collapse that leads to a supernova is ended when the core's density reaches a point where neutrons become degenerate. At this stage, neutron degeneracy pressure opposes further crush, and this resistance causes the core to rebound, producing a shock wave. Infalling material from the outer layers of the star hits this rebounding core and is met with significant resistance, leading to the star being blown apart. Neutrinos are released in vast quantities at this point, helping the shock wave in its destructive path. For cores that have a mass less than approximately three times that of the Sun, this results in a neutron star. However, if the core's mass exceeds this limit, not even neutron degeneracy can prevent the collapse, leading to the formation of a black hole.