The surprise discovery in 2013 that the tiny body Chariklo possesses rings upended the long-held assumption that only giant planets could host such features. Now, a team led by astronomer Pablo Santos-Sanz of the Instituto de Astrofísica de Andalucía in Granada, Spain, has used the James Webb Space Telescope to catch Chariklo passing in front of a background star — an event known as an occultation.
By measuring how the starlight dimmed on either side of the main body, the researchers found that one of the two rings originally detected had become noticeably denser, while the other had almost vanished. The exact cause of these changes remains unknown.
“We predict when a Solar System object passes in front of a star,” Santos-Sanz said. The brief dip in starlight reveals the object's size, shape and surroundings. He noted that such observations are “particularly challenging for minor bodies, and more challenging for distant minor bodies.”
The findings raise new questions about the composition and stability of rings around small bodies, and whether such features are more common — and more dynamic — than previously thought.