Astronomers used the James Webb Space Telescope to examine a rare class of young stellar systems called extreme debris disks, which show signs of upheaval and may offer clues about the energy involved in their collisions. In NASA’s summary of the research, the agency says the findings were published Thursday in The Astrophysical Journal.
Extreme debris disks are unusual enough that NASA says only about 1% of young stars show observable signatures of this phase, based on current observations. For this study, the team compiled 21 such systems: five from Spitzer archival data and 16 from Webb, including 12 newly observed disks and follow-up observations on four Spitzer targets, according to NASA’s write-up.
Two composition groups, and what NASA says they may mean
From that sample, the team found that the disks could be sorted into silica-rich and silica-poor groups, according to NASA’s summary of the paper. NASA says that split may help explain what kinds of collisions produced the debris.
In NASA’s account, about one-third of the sample is silica-rich, which the agency says suggests high-energy impacts between Mars-sized bodies, with enough force to vaporize a significant portion of the material. The remaining two-thirds are silica-poor, which NASA says points to smaller-scale collisions such as grazing impacts between Moon-sized objects. In a related NASA Webb post on X, the agency similarly said silica-rich disks seem to come from high-energy impacts, while silica-poor ones might form through smaller-scale collisions across a wider range of ages.
Why NASA is comparing them with our solar system
NASA says the findings may help researchers compare these young systems with models of the early solar system. In the agency’s account, the ages of the silica-rich disks observed so far fit with estimates that Earth and the Moon formed around 100 million years after the Sun formed, with the Moon likely resulting from a collision between Earth and a Mars-sized object.
NASA says that if older silica-poor disks and their irregular infrared brightening do reflect orbital instability, that would be broadly consistent with the Late Heavy Bombardment hypothesis for our solar system. That comparison depends on the condition NASA spells out, rather than establishing that our solar system definitely passed through the same phase in the same way.
NASA’s social posts leaned into that broader framing. In one post on X, the agency described planet formation as involving “violent collisions” and said Webb is helping compare other young stellar systems to our own.
