Nucleosynthesis of heavy elements: Computational experiment

The kinetic-model (KM) efficiency in heavy-element nucleosynthesis calculat ions is analyzed. Various nucleosynthesis conditions and various mathematic al models are considered. All basic two-particle reactions with neutrons, p rotons, alpha particles, and photons are taken into account. The results fo r the nuclear statistical equilibrium (NSE) model and for the KM are compar ed 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 app roximation 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 mo del at higher initial temperatures. with the results being smoothly joined by using the NSE solution as the initial KM approximation. The kinetic mode l can also be successfully used to compute the r-process under various phys ical conditions. (C) 2001 MAIK "Nauka/Interperiodica".