When does a neutron star occur?

Answer 1

A neutron star occurs when a massive star exhausts its nuclear fuel and undergoes a supernova explosion, leading to the collapse of its core. If the remaining core's mass is between about 1.4 and 3 solar masses, the gravitational pressure causes protons and electrons to combine into neutrons, resulting in an incredibly dense object primarily composed of neutrons. Neutron stars are typically around 1.4 times the mass of the sun but only about 20 kilometers in diameter, leading to extreme gravitational and magnetic fields.