Scientists Found Why Andromeda Is Making Fewer Stars, and a Small Galaxy May Be Involved

Using Hubble, researchers examined millions of stars in Andromeda and found evidence of a mystery unfolding across its spiral disk. The research, published in The Astrophysical Journal, combines data from two major Hubble surveys: the Panchromatic Hubble Andromeda Treasury and the Panchromatic Hubble Andromeda Southern Treasury. Blue stars generally indicate recent star formation, while older and redder stars reveal regions where the production of new stars has slowed. Areas with more recent star formation (1) appear noticeably bluer than regions where star formation has slowed (2). The team used data from the Panchromatic Hubble Andromeda Southern Treasury to study areas of Andromeda located near M32.