GENERAL KNOWLEDGE

Detailed explanation-1: -After a core collapse supernova, all that remains is a dense core and hot gas called a nebula. When stars are especially large, the core collapses into a black hole. Otherwise, the core becomes an ultra-dense neutron star.

Detailed explanation-2: -Supernovae occur at the end of a massive star’s life, when it is a red supergiant, with its nuclear fuel almost spent. When the central core becomes so dense that electrons and protons begin to form neutrons, it collapses catastrophically to form a neutron star.

Detailed explanation-3: -If what remains of the core of the star after the supernova explosion has a mass less than about three times the Sun’s mass, then it forms into a neutron star (if the remnant is more massive, it will collapse into a black hole). Neutron stars are fantastically dense.