A white dwarf is typically about the size of planet Earth, but will have about the same mass as the Sun. A matchbox full of white dwarf material would weigh the same as fifteen elephants.
Approximately 6% of the stars in our part of the Milky Way galaxy are thought to be white dwarfs. As red dwarfs are invisible to the naked eye, this means something like a quarter of the ones that we see as individual stars in the night sky.
A newly–created white dwarf have be as hot as any star, with a surface temperature of over 100,000 °C, but because they're so small they appear quite faint from a distance.
As there are no longer any nuclear reactions in a white dwarf, it has to rely on its store of thermal energy for all heat and light. Over time this will gradually disperse, causing the star to cool down and change colour. It will eventually disappear from sight to become a cold black dwarf.
© Haydn Thompson 2017