HED conditions at higher temperatures are important to the birth and death of stars and controlling thermonuclear fusion in the laboratory. Take as an example the birth and cooling of a neutron star. The central part of a star, ~8-20 times the mass of the Sun, fuses its way to iron and cannot go further since iron has the highest binding energy per nucleon of any element. As the iron core accumulates to ~1.4 solar masses, electron degeneracy pressure gives up against gravity and collapses. Initially the star cools by the rapid emission of neutrinos. The outer Fe surface layer (~10 K) gives rise to spontaneous pair production then reaches a temperature where the radiation pressure is comparable to the thermal pressure and where thermal pressure is comparable to coulomb interactions.