Astronomy Colloquium: Ian Roederer

Date: Wed. March 1st, 2017, 3:00 pm-4:00 pm
Location: Sears 552

Heavy Metals from the First Stars to Today

Ian Roederer (UMichigan)

NASA’s Cosmic Origins program aims to address the question, “How did we get here?”  My work addresses this question through three broad themes: the nature of the first stars, the formation and evolution of the Milky Way and Local Group, and the origin of the elements.  I study dwarf galaxies, globular clusters, and stars in the halo using optical and ultraviolet high-resolution spectroscopic data from various telescopes on the ground and the Hubble Space Telescope.  I will present observations of heavy elements that change our understanding of when and how they were first produced in the early Universe, including perhaps by the first stars.  Observations of heavy elements in a recently-discovered low-luminosity galaxy, Reticulum II, reveal that the r-process—one of the fundamental ways that stars produce heavy elements—may occur in mergers of neutron stars.  New stellar systems discovered in the near future will require lots of spectroscopic followup.  I will describe our approach to this effort and our collaborations with the nuclear astrophysics community that use these new data to better inform our understanding of nucleosynthesis and galactic formation.