A white dwarf is what stars like the Sun become after they have exhausted their nuclear fuel. Near the end of its nuclear burning stage, this type of star expels most of its outer material, creating a planetary nebula. Only the hot core of the star remains. This hot core is the new white dwarf, which typically has a temperature exceeding 100,000 Kelvin. The sun only has a temperature of 5,778 Kelvin. Which makes a young white dwarf over 17 times hotter than the sun. The white dwarf cools down over the next billion years or so unless it is accreting matter from a nearby star. When a white dwarf is finished cooling down it will still be 10,000 Kelvin, which is still 4,222 Kelvin more than the Sun's temperature. A typical white dwarf is half as massive as the Sun, yet only slightly bigger than Earth. Although a white dwarf is tiny compared to the sun, it's density is nearly the same. These stars are extremely dense due to the fact that they are so small and have so much mass. The density of a white dwarf is almost 1,000,000 times as dense as water. White dwarfs also have a low luminosity, so for us to be able to observe them, they have to be within a few hundred parsecs away from us (1 parsec = 3.26 light years). Even white dwarfs will die at some point. At the point in time when a white dwarf burns out completely, it will turn into a black dwarf. A black dwarf is the absolute last stage in life for stars that are smaller than 1.4 times the size of the sun. A black dwarf is a cold and inert stellar remnant. After our own sun has died it will turn into a white dwarf and then possibly a black dwarf.