DR5 of the R-Process Alliance: GTC sp.

We also identify one star of a possible globular cluster origin at an extremely low metallicity at [Fe/H]=-3.0. This adds to the growing evidence of a lower-limit metallicity floor for globular cluster abundances. We use the abundances of Fe-peak elements and the {alpha}-elements to investigate the contributions from different nucleosynthesis channels in the progenitor supernovae.

We find the distribution of [Mg/Eu] as a function of [Fe/H] to have different enrichment levels, indicating different possible pathways and sites of their production. We also reveal differences in the trends of the neutron-capture element abundances of Sr, Ba, and Eu of various r-I and r-II stars from the RPA data releases, which provide constraints on their nucleosynthesis sites and subsequent evolution.