The R-Process-Alliance: Tracing the nucleosynthesis history of the faint r-process enhanced metal-poor stars in the MW halo

Understanding the abundance patterns of metal-poor stars and the production of heavy elements through various nucleosynthesis processes offers crucial insights into the chemical evolution of the Milky Way. In this study, using the fifth data release from the RPA, we present detailed chemical abundances of faint and extremely metal-poor stars in the Milky Way halo. We investigate the origins of light, alpha, Fe-peak, and r-process elements to shed light on the nature of their progenitors and the astrophysical conditions in the early Galaxy. By examining the intriguing abundance patterns of carbon, Fe-peak, and alpha-elements, we probe the contributions from various nucleosynthesis channels in progenitor supernovae. Additionally, we identify globular cluster stars at very low metallicity, contributing to the growing evidence for a lower metallicity floor in globular clusters. Our findings show that the [Mg/Eu] distribution as a function of [Fe/H] indicates distinct enrichment levels across different classes of r-process-enhanced stars, suggesting multiple pathways and sites of production. Furthermore, we highlight differences in neutron-capture element trends from all RPA data releases, providing critical constraints on their nucleosynthesis origins and subsequent evolution.