What is a white dwarf made of and how does it support its own weight? Does its temperature make any difference? What will eventually happen to a white dwarf?

White dwarfs are made of degenerate matter, which is atoms with space squeezed between them; their light comes from energy stored in them from their main sequence days. How does a white dwarf support itself? It does so by the Pauli Exclusion Principle, one of my favorite astronomical principles (which also happens to remind me of someone else who is one of my favorites).

The Pauli Exclusion Principle (also known as Electron Degeneracy pressure in white dwarfs) asserts that no two fermions (particles with half integer spins, in this case electrons) can occupy the same quantum while in the same state; as a result, they fly apart, opposing the force of gravity.

However, there is a limit to electron degeneracy pressure: 1.39 solar masses, or the Chandrasekhar limit (quoting him makes me think of that person ;-) fbp). White dwarfs typically acquire the necessary mass to go supernova by accreting mass from a binary partner. If a white dwarf reaches this limit, it will explode in a type 1a supernova.

White dwarfs that never reach the Chandrasekhar limit will eventually lose their stored energy and turn into black dwarfs; black dwarfs have not yet evolved because the universe is too young.

The temperature of a white dwarf is irrelevant, in my opinion.

I meant this for you, fbp.

Either way, a white dwarf cools down and eventually becomes a black dwarf, which is essentially a cold, dark remnant. White dwarfs are primarily composed of electron-degenerate matter, mainly carbon and oxygen nuclei immersed in a sea of degenerate electrons. They support their weight through electron degeneracy pressure, which arises from the Pauli exclusion principle, preventing further collapse. The pressure is influenced by temperature, with hotter white dwarfs having higher pressure.