nucleosynthesis

The term "nucleosynthesis" refers either to the process of forming atomic nuclei from pre-existing protons and neutrons or to the process of adding nucleons to an existing atomic nucleus to form a heavier element. Nucleosynthesis occurs naturally inside stars and when stars explode as supernovae. In our standard model of cosmology, the first atomic nuclei formed minutes after the Big Bang, in the process termed "Big Bang nucleosynthesis."