Webb Telescope Detects Mars-Sized Planetary Collisions in Young Star Systems

A team led by Kate Su analyzed 21 extreme debris disks—unusual, dust-rich environments around young stars—using the James Webb Space Telescope and archival Spitzer data. The study confirmed that these disks share three defining features: unusually small dust grains, high concentrations of warm dust, and irregular infrared brightness. Spectral analysis split the sample into silica-rich disks, likely produced by energetic collisions between Mars-sized bodies, and silica-poor disks, which stem from gentler impacts such as grazing Moon-sized encounters.

Silica-rich disks are found only around stars younger than 300 million years, whereas silica-poor disks occur across a broader age range and show stronger brightness fluctuations. These observations provide a window into the violent processes that may have shaped our own Solar System, including the giant impact that formed the Moon. The findings also offer clues about later instability phases, potentially linked to events like the Late Heavy Bombardment.