What happens to the core of a supernova with less than three times the mass of the sun?

In the context of stellar evolution, when a massive star undergoes a supernova explosion, the fate of its core is determined by its mass. For a core with less than three times the mass of the sun, the remnant after the explosion is a neutron star.

This phenomenon occurs because, during the supernova event, the outer layers of the star are ejected, while the core collapses under the force of gravity. If the core is below the threshold of about three solar masses, the gravitational collapse is halted by the neutron degeneracy pressure. This pressure arises from the Pauli exclusion principle, which prevents two neutrons from occupying the same quantum state, thus stabilizing the core against further collapse.

In contrast, cores that exceed this mass limit may collapse further into black holes, while lower mass remnants, such as those from less massive stars, will evolve into white dwarfs instead of neutron stars. Therefore, the formation of a neutron star is specific to the mass range of the collapsing core, which in this case is up to three solar masses.