s-Process and solar abundances

The origin and distribution of the heavy elements (A > 56) are attributed to a large extent to s-process nucleosynthesis. Structures from the s-process are clearly visible in the distribution of solar abundances. It is shown that the s-process abundances are a superposition of different s-process components which are distinguished both by the character and strength of the neutron exposure. Exponential exposure distributions, single flux exposures and pulsed irradiations are treated to find the best reproduction of the s-only isotopes. An important prerequisite for the analysis in these terms is a reliable input basis, especially of the neutron capture rates of all the nuclei on the synthesis path. Special cases are discussed in connection with their application in the calculations. s-Process branchings are examined because of their crucial role in elucidating the nature of the s-process. Finally, a decomposition of heavy solar abundances into its s- and r-process contributions is presented