# Is a small fragment of a white dwarf stable? [duplicate]

Assuming it is somehow possible to get a small piece of a white dwarf (maybe a dice) and this piece escapes into free space. Would that piece of white dwarf matter keep its density/state, or would it expand, explode, or transform into another state without the huge gravitational force of the whole white dwarf it was captured in before?

There is a similar question here for neutron stars: What would happen to a teaspoon of neutron star material if released on Earth?. Neutrons decay without the large pressure inside the neutron star, so the fate of a piece of neutron star material is clear. But what would happen to white dwarf material? I think the state of white dwarf matter is different from neutron stars (which mainly consists of neurons...)?

• The decay of neutrons is a minor (and slow) contributor to the energy released from unconstrained neutron star matter. May 11, 2021 at 23:11

At typical densities for white dwarfs of $$10^{9} - 10^{11}$$ kg/m$$^3$$, the internal kinetic energy density of the electrons in the degenerate gas is very high - of order $$10^{22}$$ to $$10^{25}$$ J/m$$^3$$. This energy would be "released"/explode if the white dwarf material is unconfined by gravity. Note that this would be true, even if the white dwarf material was cool, since the kinetic energy density of a degenerate gas is independent of temperature and the ions in the gas are minor contributors to the overall kinetic energy.
• @Alchimista it isn't equal to $P$ except to a small numerical factor. The pressure is 2/3 the kinetic energy density for non-relativistic degeneracy and 1/3 for ultra-relativistic degeneracy. See any statistical mechanics textbook. There is no pressure without kinetic energy. That is "kinetic theory". May 12, 2021 at 13:38
• @Alchimista $T$ plays no role in the pressure of a degenerate gas. May 12, 2021 at 15:22