When does a newborn neutron star freeze solid?

After a supernova, a hot protoneutron star cools by radiating neutrinos. Researchers derived a closed-form equation for when this cooling allows heavy nuclei in the outer layers to crystallize into a solid crust, accounting for the star's mass, radius, and composition. The formula predicts crust formation at 100–500 seconds post-birth and clarifies how composition and cooling rate control the timing.