MOSCOW, ID – Astronomers have identified a new moon orbiting Uranus with the aid of NASA’s James Webb Space Telescope, and a University of Idaho professor played a key role in the discovery.

The satellite, temporarily designated S/2025 U1, becomes the planet’s 29th confirmed moon. The team, led by the Southwest Research Institute, included U of I physics professor Matthew Hedman. Using Webb’s Near-Infrared Camera, scientists captured 10 long-exposure images in February 2025, which were later processed and analyzed over several months.

At just six miles in diameter, the newly found moon is among the smallest known satellites of Uranus. It orbits within a cluster of tightly packed small moons, contrasting with the five larger moons that circle farther from the ice giant. Hedman explained that these close orbits often lead to gravitational interactions and possible collisions.

“One of the things that convinced us that we had a new moon was that we saw it in all 10 pictures, and it was roughly the same brightness in all 10 pictures,” Hedman said. The object’s speed and movement also matched expectations for Uranus’s gravity.

The discovery could shed new light on how Uranus’s moons interact and whether smaller satellites influence the structure of the planet’s rings. Hedman and his graduate students plan to continue analyzing Webb’s imagery to better understand these dynamics and search for additional, previously undetected moons.

S/2025 U1 will eventually receive an official name from the International Astronomical Union, which traditionally names Uranus’s moons after characters from Shakespeare and Alexander Pope.

The project received $18,663 in funding from the NASA Space Telescope Science Institute, with 100 percent of the funding federally supported.