Nuclear aspects of stellar and explosive nucleosynthesis

The majority of nuclear reactions in astrophysics involve unstable nuclei which are not yet fully accessible by experiments. Therefore, there is high demand for reliable predictions of cross sections and reaction rates by theoretical means. The majority of reactions can be treated in the framework of the statistical model (Hauser-Feshbach). The global parameterizations of the nuclear properties needed for predictions far off stability probe our understanding of the strong force and take it to its limit. The sensitivity of astrophysical scenarios to nuclear inputs is illustrated in the framework of a detailed nucleosynthesis study in type II supernovae. Abundances resulting from calculations in the same explosion model with two different sets of reaction rates are compared. Key reactions and required nuclear information are identified.