The R-Process-Alliance: Finding metal-poor r-process stars to understand heavy element nucleosynthesis

Understanding the origin of the heavy elements has been a decades-long pursuit, with many open questions remaining. Old stars found in the Milky Way can provide answers because they preserve clean element abundance patterns of the nucleosynthesis processes that operated some 13 billion years ago, including those of the r-process. The R-Process-Alliance (RPA) aims at systematically identifying metal-poor r-process stars to reconstruct the origins of these elements and chemical evolution of heavy elements. This talk focuses the what the RPA's detailed heavy element abundance measurements in many r-process stars can tell us about the astrophysical sites of heavy element nucleosynthesis, actinide production, and fission recycling.