What remains after a dwarf star such as our own has cooled off?

When it reaches the end of it's life, it will swell, engulf most of the inner planets, and then throw a lot of it's mass into space. Leaving a small smoldering cinder in it's place.


But what happens when that cools down? What is left when a star shuts completely down and freezes?|||The universe freezes over. Seriously... a dwarf star is very dense and has an enormous heat capacity. At the same time it has a very small surface area (for a star). So it takes a long time for the white dwarf to cool down. The total luminosity goes with T^4, so every time the temperature goes down by a factor of 10, the time to cool down by the same factor goes up by a factor of 10000. While this is not quite correct for very low temperatures (the heat capacity is not a constant for T-%26gt;0 but starts to fall quickly once quantum mechanics sets in), the white dwarf will stay classical and thus "warm" for a long time (long as in 10^30+ years). Moreover, if dark matter annihilates inside stars, there will be a heat source independent of stored heat and the remnant nuclear processes, crystallization etc.





I believe these stars will stay warm longer than it takes for them to collide and slowly form black holes, the last stage of matter in the universe. And in the end all the dwarfs will be merged to black holes and for the coming era up to 10^100 years black holes will rule.|||depending on the size of the star





supernova





white dwarf





a cold lump of carbon





neutron star





a black hole





i beleive...i had astromony in like 4th grade, but i think you're looking for the cold lump of carbon.|||Coldness, blackness and death and still hostile coldness (=no energy for life as we know)|||Our sun is of the size that is believed to end up as a black dwarf. You're right, it turns into a white dwarf, but soon after, in astronomical time scale, it runs out of fuel for fusion. As hot and dense as the white dwarf is, it simply is not hot enough to fuse all the way up to iron. So the star just has residual heat, and slowly cools. This heat lasts a long time. It's believed that in the history of the universe, no white dwarf has yet cooled to say, room temperature.|||When our sun is a white dwarf, with no nuclear fuel it will radiate its left-over heat for billions of years. When its heat is all dispersed, it will be a cold, dark black dwarf - essentially a dead star perhaps filled with diamonds, highly compressed carbon.|||comment to amansscientiae: the whole universe won't freeze.. hell no, if it is only our sun that does freeze, billiobs, possible trillions, even, of other stars are out there that will radiate heat to the rest of the universe





if our sun does 'die out' or run out of fuel in which it is no longer able to support nuclear fission and fusion (in other words, incapable of producing heat and light), it will cease to exist. as simle as that, our sun in its white dwarf form will be a goner