  Abundances of low-metallicity stars offer a unique opportunity to understand
the contribution and conditions of the different processes that synthesize
heavy elements. Many old, metal-poor stars show a robust abundance pattern for
elements heavier than Ba, and a less robust pattern between Sr and Ag. Here we
probe if two nucleosynthesis processes are sufficient to explain the stellar
abundances at low metallicity, and we carry out a site independent approach to
separate the contribution from these two processes or components to the total
observationally derived abundances. Our approach provides a method to determine
the contribution of each process to the production of elements such as Sr, Zr,
Ba, and Eu. We explore the observed star-to-star abundance scatter as a
function of metallicity that each process leads to. Moreover, we use the
deduced abundance pattern of one of the nucleosynthesis components to constrain
the astrophysical conditions of neutrino-driven winds from core-collapse
supernovae.
