  We compare three different statistical models for the equation of state (EOS)
of stellar matter at subnuclear densities and temperatures (0.5-10 MeV)
expected to occur during the collapse of massive stars and supernova
explosions. The models introduce the distributions of various nuclear species
in nuclear statistical equilibrium, but use somewhat different nuclear physics
inputs. It is demonstrated that the basic thermodynamical quantities of stellar
matter under these conditions are similar, except in the region of high
densities and low temperatures. We demonstrate that mass and isotopic
distributions have considerable differences related to the different
assumptions of the models on properties of nuclei at these stellar conditions.
Overall, the three models give similar trends, but the details reflect the
uncertainties related to the modeling of medium effects, such as the
temperature and density dependence of surface and bulk energies of heavy
nuclei, and the nuclear shell structure effects. We discuss importance of new
physics inputs for astrophysical calculations from experimental data obtained
in intermediate energy heavy-ion collisions, in particular, the similarities of
the conditions reached during supernova explosions and multifragmentation
reactions.
