University of Notre Dame researchers, along with collaborators in China and Australia, published a new sample catalog of more than 24 million stars that can be used to decipher the chemical history of elements in the Milky Way Galaxy.
Summary of the astrophysical parameters reported in this work, which in combination constrain the assembly and chemical evolution of the Milky Way. Credit: University of Notre Dame The research, published this month in The Astrophysical Journal, represents about one-hundredth of a percent of the roughly 240 billion stars in the Milky Way. It marks a milestone for Timothy Beers, the Grace-Rupley Professor of Physics at Notre Dame, who has spent most of his career planning and executing ever-larger surveys of stars to decipher the galaxy's formation and chemical evolution—a field called galactic archaeology. Researchers employed a new approach to measure the light from each star to infer the abundances of heavy metals such as iron. They also measured their distances, motions and ages. "The elemental abundances of individual stars trace the chemical enrichment of the Milky Way galaxy, from when it first began to form stars shortly after the Big Bang to the present," Beers said. "Combining this information with the stellar distances and motions allows us to constrain the origin of different components in the galaxy, such as the halo and disk populations," he continued. "Adding age estimates puts a `clock' on the process, so that a much more complete picture of the entire process can be drawn." Previous…