A white dwarf about the size of the earth but with a mass of a star leads to a very high density. An atomic structure where the electrons are packed very close the the nucleus, otherwise know as degenerate matter. Correct me if I'm wrong; this is due to cold temperatures. Then how come white dwarfs are located the bottom left of the Hertzsprung - Russel diagram marked with low Absolute Magnitude and lumosity but high surface temperature? In order for electrons to be packed tightly near the nucleus wouldn't the temperature have to be near 0 Kelvin? Thnx Sorry I don't have a link for the HR diagram, I'm getting it from a book.