How is neutron degenerate matter created?

Answer 1

Neutron stars are created when a massive star runs out of hydrogen to burn and become a supergiant. The supergiant will then explode and only leaves a core and a nebula. The dense core will then become a neutron star or a black hole.

Answer 2

Neutron degenerate matter forms when the core of a massive star stops producing energy and collapses under the force of gravity while the outer portions are blasted away in a supernova explosion. The gravity causing the core to collapse is so strong that protons and electrons merge to form neutrons, forming an extremely dense object called a neutron star. Neutron stars can only form with cores in a specific range of masses. At less than 1.4 times the mass of the sun, gravity will not be strong enough to overcome electron degeneracy pressure and a less dense object called a white dwarf will form. If the core is greater than 3 solar masses than not even neutron degeneracy pressure will be able to stop the collapse, and the core will become a black hole.