Neutron reactions within stars

Regarding evolution of stars nuclear reactions, especially the reactions of neutrons with protons or nuclei, are very important. It is supposed that heavy nuclei are formed by neutron capture by nuclei of the ferrous group. These neutron syntheses of heavy nuclei, which represent a significant stage in the evolution of stars, are divided into a slow s process and a fast r process. For both processes the main characteristics are given. Features and physical conditions of evolution processes are discussed and the dependence of Fermi energy on the density of matter consisting of nuclei is outlined