Hubble Finds Andromeda Star Formation Fell to One-Fifth in 40 Million Years as M32 Draws Blame
Updated
Updated · Space.com · Aug 10
Hubble Finds Andromeda Star Formation Fell to One-Fifth in 40 Million Years as M32 Draws Blame
3 articles · Updated · Space.com · Aug 10
Summary
Hubble data show Andromeda’s star formation has dropped sharply over the past 40 million years, leaving the galaxy now producing only about one-fifth of the sun’s mass in new stars each year.
200 million stars mapped across two-thirds of Andromeda’s disk let astronomers reconstruct when different regions stopped forming stars, revealing an especially strong slowdown on one side beginning about 60 million years ago.
M32, a small companion galaxy just 16,000 light-years from Andromeda, is the leading suspect because that weakened side faces it and the dwarf may be the stripped remnant of an earlier collision.
Earlier work had shown Andromeda underwent a star-formation burst about 2 billion years ago and then declined; the new result pins down how abruptly that deceleration accelerated in recent cosmic time.
Late-August launch plans for NASA’s Nancy Grace Roman Space Telescope could soon extend the picture beyond Hubble’s reach and test whether M32 truly drove the slowdown.