Dust around other stars can preserve clues to collisions between large rocky bodies. Astronomers used Webb to examine extreme debris disks, systems with unusually large amounts of warm dust, in research announced on October 1.
The telescope did not film planets smashing together. It measured the material left around stars. Its composition gives the team a way to infer how energetic the events that produced it may have been.
Kate Su of the Space Science Institute led the work. The team studied systems in a stage after the gas-rich disk in which planets first form, when dust and larger debris remain around the star.
About one-third of the sample was rich in silica, according to NASA's account. The researchers interpret that as evidence for high-energy impacts involving Mars-sized bodies, with substantial amounts of rock turned into vapor.
The remaining two-thirds was silica-poor. The team associates those systems with smaller-scale events, including grazing collisions involving Moon-sized objects. These are interpretations of the dust signatures, not direct measurements of the colliding bodies' sizes.
Silica-rich disks appeared only around stars younger than 300 million years in the sample. The other group spanned a wider range of ages and often changed brightness more strongly.
The comparison helps researchers examine processes relevant to the formation of rocky planets, including our own system's proposed history of large impacts. The observable evidence is the debris those events leave behind.
