Black Hole:A black hole is an extremely dense and massive object in space with a gravitational field so strong that nothing, not even light, can escape from it.
Neutron Star:A neutron star is the extremely dense, collapsed core of a massive star that remains after the star has exploded as a supernova, leaving behind a rapidly spinning, highly magnetized object.
White Dwarf:A white dwarf is a small, dense star composed of degenerate matter, which is the end-state of a low- to medium-mass star that has shed its outer layers and no longer undergoes nuclear fusion.