Galactic Archaeology in Search of the First Stars

The first stars in the Universe were the first sources of light and heavy elements. Their unusual metal-free composition means they were probably all massive stars, but the complex physical processes that determine the stellar mass are poorly understood, and they are too distant to see directly with even the most advanced observatories. We are now studying the detailed chemical abundance patterns of surviving low-mass, long-lived stars in the stellar halo of the Milky Way to learn about the first, metal-free stars that created the heavy elements we see in their atmospheres. To do this, we are creating a "virtual Galaxy" that accurately models the real accretion history of the Milky Way and relates the low-redshift "fossil record" with the earliest times.