Massive stars ends their life as either black holes or neutron stars, while the medium or low mass stars (stars with mass less than about 8 times that of Sun) ends their life as White dwarfs. Such low or medium mass stars, during the end of their nuclear fuel, expel most of its outer material, creating a planetary nebula. Only the hot core remains at the center. This hot core is referred as white dwarf. White dwarf is basically a stellar core remnant.

White dwarfs is as massive as our Sun, but only as big as our Earth in size. White dwarfs cool down and keep loosing energy over the next billion years or so.

Black Dwarf

A black dwarf is a white dwarf that has sufficiently cooled down that it no longer emit any significant or measurable heat or light. No black dwarf are expected to exist in the universe because the time required for a white dwarf to reach the black dwarf stage is calculated to be longer than the current age of the universe itself.

See also

• Red Dwarf
• Brown Dwarf