How small and heavy is a white dwarf in real physical terms?

Question

When a star collapeses in on itself it is suppose to become super heavy and dense, very very small and is the start of a black hole. But exactly how small, heavy are we talking do we know or is just theory??

Answer 1

A white dwarf is about 100 times smaller than the Sun, which is about the same size as the Earth, and a million times more dense than the Sun, with a density of 10^9 kg·m−3.

A neutron star is only about 10 miles in diameter and has a density between 10^12 and 10^15 g/cc, which is about the same as an atomic nucleus.

A black hole is a singularity, which in this case basically means an infinitely small and dense object.

Answer 2

Most stars do not collapse into a black hole. The life evolution of a star depends on its mass. Only the most massive stars collapse into a black hole at the end of their lives. Most stars will end up being a white dwarf or brown or red dwarf. The mass limit for a white dwarf is about 1.4 solar masses.


"Many white dwarfs are approximately the size of the Earth, typically 100 times smaller in diameter than the Sun; their average mass is about 0.5-0.6 solar masses, though there is quite a bit of variation.(see link for discussion) Their compactness implies that the same amount of matter is packed in a volume that is typically 1003 = 1,000,000 times smaller than the Sun and so the average density of matter in white dwarfs is 1,000,000 times greater than the average density of the Sun." -Wikipedia.

Answer 3

Typical white dwarfs that we observed are half as massive as the Sun and slightly bigger than the Earth. White dwarf s are one of the densest forms of matter, surpassed only by neutron stars.