black dwarf star

A black dwarf star is the theoretical final stage in the evolution of a white dwarf star. White dwarfs are the remnants of stars with low to intermediate mass, like our Sun, after they have exhausted their nuclear fuel. These dense, compact objects, roughly the size of Earth but with a mass similar to the Sun, are supported by electron degeneracy pressure rather than normal gas pressure.12

Initially, white dwarfs are hot and emit light. Over billions of years, they are expected to cool down until they no longer radiate any detectable light, at which point they become a black dwarf. This process is so lengthy that no black dwarfs are believed to exist yet in the universe.123