Field guide · Stars
StarWhite dwarf
The exposed core of a dead Sun-like star: as massive as the Sun, as small as the Earth, and cooling slowly for billions of years.
- Mass
- Up to about 1.4 Suns
- Size
- About the Earth’s
- Nearest
- Sirius B, 8.6 light-years
When a star like the Sun has shed its outer layers as a planetary nebula, what remains is its core, no longer making energy, just glowing with stored heat. It is so dense that a teaspoon would weigh several tonnes.
The first one found was the faint companion of Sirius. Friedrich Bessel inferred it in 1844 from Sirius’s wobble; Alvan Clark saw it in 1862 while testing a new telescope lens. Its size baffled astronomers for decades, until quantum physics explained what holds such a thing up.
None of them are visible to the naked eye, but they are the most common end of all: the Sun will be one.
See it in the sky
Each one opens the sky map pointed at it, for tonight, from where you are.