Stellar matter in supernova explosions and nuclear multifragmentation

During the collapse of massive stars and type-II supernova explosions, stellar matter reaches densities and temperatures which are similar to ones obtained in intermediate-energy nucleus-nucleus collisions. The nuclear multifragmentation reactions can be used for determination of properties of nuclear matter at subnuclear densities, in the region of the nuclear liquid-gas phase transition. It is demonstrated that the modified properties of hot nuclei (in particular, their symmetry energy) extracted from the multifragmentation data can essentially influence the nuclear composition of stellar matter. The effects of the modification of nuclear properties on weak processes and on nucleosynthesis are also discussed.