Rana Ezzeddine

The oldest, most metal-poor stars found in the Galactic halo and satellite dwarf galaxies retain in their atmospheres the chemical footprints of the high redshift Universe. Employing “stellar archaeology” – the diverse use of the chemical and dynamical properties of metal-poor stars – outstanding questions about the early Universe can be answered. Using high resolution optical and UV spectroscopic observations of the dataset of the most chemically interesting metal-poor stars, I aim to probe the nature of the first stars and supernovae explosions (SNe), the relevant nucleosynthesis processes responsible for the formation and evolution of the elements as well as early star and galaxy formation processes. I will discuss how we I’ve used the most metal-poor Galactic stars to help elucidate the nature of their first star progenitors and mechanisms of the SNe responsible for their chemical signatures. I will highlight how these metal-deficient stars could be used to place constraints on modelling of non-equilibrium steady-state systems, as applied to studies of stellar and planetary atmospheres. Additionally, I will explore major recent advancements in our understanding of the heaviest elements formation in metal-poor stars via the r(apid) neutron capture r-process, especially in light of the ground-breaking gravitational wave discovery of the binary neutron star mergers event GW170817.