Scientists think a Mars-sized object once smashed into the young Earth, and some of the debris later formed the Moon. Now NASA's James Webb Space Telescope has studied young star systems that show signs of similar violent crashes. These systems are called extreme debris disks. They hold unusually large amounts of warm dust close to the star, in a zone like the one where our solar system's rocky planets orbit.
Such disks are rare. Based on current data, only about one percent of young stars show signs of this phase. Even so, the team gathered a sample of 21 disks, 16 of them observed by Webb. Lead author Kate Su said it was the first time researchers had enough systems to truly understand this group. The disks share three features: dust grains smaller than in planet-forming or ordinary debris disks, plenty of warm dust, and irregular changes in brightness. The results, published in The Astrophysical Journal, may help explain how planets form and evolve.