white dwarfs

A white dwarf is the remnants of a star that has exhausted its nuclear fuel, typically after evolving from a red giant stage. These stars are extremely dense and compact, with a mass comparable to the Sun but a volume similar to Earth. White dwarfs no longer undergo fusion reactions, so they gradually cool and fade over billions of years. They emit light primarily due to residual heat. Ultimately, they may become black dwarfs, which are theoretical objects that no longer emit significant heat or light, although the universe is not old enough for any to exist yet.