Andromeda star formation decline study

A new study using data from United States — NASA's Hubble Space Telescope finds that star formation in the Andromeda galaxy has declined over the past 500 million years, with a steeper drop in the last 40 million years. The research, published in The Astrophysical Journal on July 27, 2026, combined data from two Hubble surveys (PHAT and PHAST) to map two-thirds of Andromeda's disk and measure about 200 million individual stars. The team found that star formation peaked about 2 billion years ago, likely due to a merger, and has since declined. The current rate is about one-fifth of a solar mass per year. The decline is concentrated in a star-forming ring about 32,000 light-years from the center. The study also investigated the possible role of the satellite galaxy M32, finding a localized decrease in star formation near it that began about 60 million years ago, but the connection remains inconclusive. The team plans to continue analysis and use data from the upcoming Nancy Roman, scheduled to launch as early as August 30, 2026.