Nucleosynthesis of heavy elements: Computational experiment

The kinetic-model (KM) efficiency in heavy-element nucleosynthesis calculations is analyzed. Various nucleosynthesis conditions and various mathematical models are considered. All basic two-particle reactions with neutrons, protons, alpha particles, and photons are taken into account. The results for the nuclear statistical equilibrium (NSE) model and for the KM are compared under various ambient conditions. The time it takes for the solution to become a steady state one is estimated in the KM, provided that the NSE approximation holds. The computational processor time for temperatures T < 8 x 10(9) K is shown to be modest, and the KM can be used for nucleosynthesis calculations in this range. The KM can he realized together with the NSE model at higher initial temperatures. with the results being smoothly joined by using the NSE solution as the initial KM approximation. The kinetic model can also be successfully used to compute the r-process under various physical conditions. (C) 2001 MAIK Nauka/Interperiodica.