So our white dwarf survives, not by internal combustion, but by quantum mechanical principles that prevent its complete collapse. This is because the more mass a white dwarf has, the more its electrons must squeeze together to maintain enough outward pressure to support the extra mass. There is a limit on the amount of mass a white dwarf can have, however. With a surface gravity of 100,000 times that of the earth, the atmosphere of a white dwarf is very strange. The heavier atoms in its atmosphere sink and the lighter ones remain at the surface.
Some white dwarfs have almost pure hydrogen or helium atmospheres, the lightest of elements.
Underneath the atmosphere, scientists believe there is a 50 km thick crust, the bottom of which is a crystalline lattice of carbon and oxygen atoms. Show me a printable version of this page. Please let us know .