Tracing Galactic History: Age and Motion in the Milky Way Disk

Weixiang Sun et al. studied over 230,000 red clump stars to explore how stellar motions vary with age across the Milky Way’s thin and thick disks. They found that older stars have higher velocity dispersions, with differences shaped by processes like giant molecular cloud heating, spiral arms, and galaxy mergers. The study highlights the thin disk’s gradual heating and the thick disk’s turbulent formation, offering insights into the Milky Way’s dynamic history.