Astronomers have used NASA's James Webb Space Telescope to study extreme debris disks: young star systems with unusually large amounts of warm dust close to the star. The dust is thought to come from violent collisions between planetary bodies, similar to the impact that is believed to have formed our Moon. The results were published on 1 October 2026 in The Astrophysical Journal.
What extreme debris disks are
NASA's retired Spitzer Space Telescope discovered this subclass of debris disks. According to NASA, scientists estimate that only about 1 percent of young stars show observable signs of this phase.
What the team found
- A sample of 21 extreme debris disks: five from Spitzer archive data and 16 observed with Webb, including 12 newly observed disks.
- Three shared properties: smaller dust grains, a high concentration of warm dust and irregular brightness variations.
- About one third of the disks are silica-rich, pointing to high energy impacts between Mars-sized bodies. Two thirds are silica-poor, suggesting smaller, grazing collisions between Moon-sized objects.
This is the first time we have gathered enough systems to truly understand this subclass that we call extreme debris disks.Kate Su, Space Science Institute, lead author
Why it matters
The findings help explain how rocky planets form and how our own solar system may have looked during its formation. Webb's view relies on its position near the Sun–Earth L2 point, explained in our guide to Lagrange points.
Frequently asked questions
What is an extreme debris disk?
A young star system with unusually large amounts of warm dust close to the star, thought to come from collisions between planetary bodies.
How many extreme debris disks did the study include?
21, according to NASA: five from Spitzer archive data and 16 observed with Webb.
Related reading
Sources
Cover image: Artist's concept of a dusty debris ring in a young planetary system, based on Spitzer observations. Credit: NASA/JPL-Caltech (PIA07096), public domain.