Establishing the Properties of the First Stars and Supernovae and the Origins of the Heaviest Elements with Stellar Archaeology

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The Big Bang left behind the Universe made from just hydrogen, helium, and tiny amounts of lithium. With time more and more of all heavier chemical elements from the Periodic Table were produced in stars, supernova explosions, and mergers of neutron stars. Astronomers study old stars to understand the cosmic history of the elements and how their presence has influenced star and galaxy formation throughout cosmic time. These stars are over 13 billion years old and thus formed very early in the Universe soon after the Big Bang. These low mass stars change very slowly with time and so preserve a "chemical fingerprint" of the Universe at the time they formed. The investigator intends to organize observations of stars into a chemical sequence leading to a better understanding of the elements that we find on Earth. The investigator will expand upon her public education efforts by working with undergraduate students to produce videos describing the astronomical connection to common consumer products. The videos will be distributed through the institution's outreach program and the students will gain skill in media work and science communications.The investigator will use the large Magellan telescope in Chile to observe these old stars in the Milky Way galaxy and small satellite dwarf galaxies. This will enable her to unlock critical information about the very first stars that first lit up the Universe and the associated first element production events that cannot be obtained with any other method. It will also provide long-missing details about the production sites of the very heaviest elements, e.g., silver and gold. She will also search for surviving first galaxies using stellar chemical composition as a key indicator. Altogether, this enables her to reconstruct how the Universe evolved from just a few stars into today's rich and complex Universe. Her results will guide many research areas such as early star and galaxy formation, nuclear physics, stellar nucleosynthesis, dwarf galaxies, formation of the Milky Way, and complement far-field observations to be obtained with current and next generations of telescopes.