Insights into the early Galactic history from metal-poor stars

Speaker: Miho Ishigaki (Subaru telescope, NAOJ)


Metal-poor stars are the main constituents of the stellar halo of the Milky Way, which is presumably one of the oldest stellar components of our Galaxy. Because of their pristine chemistry and long dynamical time, metal-poor stars provide rich information about the chemodynamical evolution of our Galaxy. Massive surveys of Galactic stellar populations such as SDSS and Gaia in the last 20 years have revealed an unprecedented number of substructures of metal-poor stars, which have revolutionized our understanding of the early Galactic history. Chemical elements in stellar atmosphere have been particularly powerful to infer birth environment of individual metal-poor stars. I would like talk about progress of observations of metal-poor stars in the past 10 years, mainly focusing on spectroscopic observations and their interpretation. I also discuss prospects with the Prime Focus Spectrograph on the Subaru Telescope to study relatively unexplored outer halo region of our Galaxy.