Astronomy Colloquium

Detailed elemental abundances of surviving old stars provide an archaeological window to the first stars and galaxies. Using these measurements requires building up our understanding of the nuclear and stellar astrophysics that produce different elements and connecting them to galaxy formation and cosmology. I will show how stellar abundances of metal-poor stars have shaped our current understanding of the rapid neutron-capture process (r-process), including how they inform future multi-messenger observations of kilonovae. The r-process can in turn be used to build our understanding of the high-redshift universe, including galaxy formation in the faintest dwarf galaxies and the hierarchical assembly of our Milky Way's stellar halo.