ocr: WHITE DWARF When a star of a certain size (less than 8 solar masses) has used up its fuels for fusion reactions, it goes through a giant phase and then ends up as a dense star about the size of the Earth, weighing about the mass of the Sun or less. A star like this is called a white dwarf. The name white dwarf is misleading, as the star's colour changes with age, sometimes ending as a black sphere, called a black dwarf. There are an estimated ten billion white dwarts in our Galaxy. The more mass a dwarf has, the smaller its diameter and greater its density. The density of a typical white dwart ...
