The Origin of the Metal-Poor Halo of the Milky Way

Professor Frebel will reconstruct the origin of the Milky Way's stellar halo by studying the chemical compositions of its constituents: extremely metal-poor stars in the halo itself and metal-poor stars in the least luminous dwarf galaxies orbiting about the Galaxy. She will leverage her access to the Australian SkyMapper Telescope to identify large numbers of stars in the Galactic halo, and combine these data with high spectral resolution observations using the Magellan telescope. She will therefore assemble a legacy data set of the most metal-poor stars in the galaxy, which will substantially advance our understanding of the early universe and the build-up of the old stellar halo of the Milky Way. In concert, the PI will produce accompanying theoretical frameworks that allow for a cosmologically informed interpretation of stellar abundance measurements. The program has three specific goals: (1) to perform stellar archaeology, giving us new constraints on the major physical processes that drove early star formation; (2) to perform dwarf-galaxy archaeology, allowing us to better understand galaxy formation; and (3) to determine the role of metal-poor stars as tracers of the accretion history of the Milky Way halo.

Frebel will disseminate research to a broad audience by publicly releasing her new measurements on the chemical abundances of stars. She will also collaborate closely with the MIT Online Science, Technology, and Engineering Community (MOSTEC), which is a free online education and enrichment program for high school seniors from underserved and underrepresented communities. Finally, the PI will also create a series of short videos designed to show students how to observe with the Magellan telescopes, thereby encouraging them to be informed participants in how astronomical data are gathered.