| Abstract : | Detection of lanthanides from the red kilonova spectra of GW170817 has shown clear evidence of r-process production during neutron star (NS) merger events. However, the detection of r-process-rich stars in the very early Galaxy, as well as in some of the primordial Milky Way satellites, pose a challenge to r-process production due to NS mergers at earlier times. Here, we present detailed chemical abundances of four r-I stars using the 10-m Gran Telescopio Canarias GTC, including thorium abundances for two stars using R=25000 high signal-to-noise spectra. We discuss r-process-rich stars across various metallicities in the Galaxy as well as possible connections between different types of r-process-rich stars, e.g., r-I, r-II stars, and its progenitor sites. We also show the kinematic analysis of the sample to assess their assembly history in the Galaxy. To understand the progenitor sites, we use differential analysis to derive precise abundances between r-II and r-I stars. |
