Mass fractions in stellar interior during presupernova evolution

Abstract

We assume nuclear statistical equilibrium (NSE) conditions and use Saha Equation to calculate mass fractions in stellar interior during presupernova evolution of massive stars. Our ensemble contains 728 nuclei. The distinguishing feature of our calculation is a state-by-state summation of nuclear level densities up to 10 MeV for all nuclei considered in our ensemble. This leads to a more realistic description of nuclear partition function which poses one of the largest uncertainties in the mass fraction calculations under conditions of NSE. The Coulomb correction term was taken into account for the calculation of ground-state binding energies of the nucleons. Our calculated mass fractions are up to four orders of magnitude smaller than previous calculation. The current calculation could prove useful for study of stellar matter during presupernova phases of massive stars.