WHere does the energy emitted by a white dwarf come from?

Question

Iron fusion, carbon fusion, thermal cooling, helium fusion, or all of them?

Answer 1

a white dwarf is done fusing all of its elements and is composed almost entirely of electrons. all of its energy and light are from leftover heat. so the answer is thermal cooling.

EDIT: o and heres a little tip. any time you see iron fusion you can rule that out because iron fusion doesnt occur in stars because it doesnt give off energy it requires energy.

Answer 2

Check out this link; It talks about white dwarfs emissions coming form two closely paired dwarfs and white dwarfs with planetary systems, but not just a single dwarf.
Type of emissions : Electrically-powered x-ray …
so the Iron fusion, carbon fusion, thermal cooling, helium fusion, have all taken place before the star went into the dwarf phase.

Answer 3

Thermal cooling from when the stars core contracted. This yielded alot of gravitational energy and will take many billions of years to radiate off inot space. No more fusion can occur unless another nearby star dumps matter onto the white dwarf.

Answer 4

A white dwarf is the super-hot core of a red giant; It's not fusing anything any longer - and with it's limited surface area (a white dwarf is about as big as the Earth or a little larger), it'll take millions to billions of years to cool off. If the sun died, and remained the size it is today - it would cool off much, much faster.

Answer 5

White dwarfs don't produce any energy. The light they give off is from residual heat from when the star was alive.

Answer 6

It is radiating the immense latent heat that resulted from the gravitational collapse of a star in the final stage of life.