Astronomers Define Milky Way's Star-Forming Boundary, Revealing New Galactic Insights
An international team of astronomers has successfully pinpointed the boundary of the Milky Way's star-forming disk, a longstanding question in Galactic archaeology. By examining the ages of stars, researchers determined that most star formation occurs within about 40,000 light-years of the Galactic Center. This discovery was made by combining measurements of bright giant stars' ages with advanced galaxy evolution simulations, revealing a 'U-shaped' pattern in stellar age distribution. This pattern marks the outer limit of active star formation in the Milky Way. The study highlights the inside-out growth of galaxies, where star formation begins in dense central regions and spreads outward over billions of years. The findings also explain why stars exist beyond the star-forming edge, attributing it to radial migration, where stars gradually move outward from their birthplaces. 
