Exploring Stellar Halos: Unraveling Cosmic Histories with Chemical Clues

Stellar halos, the faint outskirts of galaxies, hold clues about galaxy formation. Using simulations, researchers divided halo stars into ex-situ, endo-debris, and in-situ categories, tracing their origins and chemical fingerprints. Most halo stars come from merged galaxies, with larger halos requiring more mergers. The study revealed a clear mass-metallicity relationship, linking chemical patterns to galaxy formation histories and enhancing our understanding of cosmic evolution.