New Moon Discovered Orbiting Uranus

Researchers, including Dr. Mark Showalter and Dr. Matthew Tiscareno of the SETI Institute, along with colleagues at the Space Telescope Science Institute (STScI), discovered a previously unknown moon of Uranus using the James Webb Space Telescope (JWST). Astronomers detected the faint object on February 2, 2025, in a series of 10 long-exposure images. This discovery adds a new member to Uranus’s family of satellites, bringing the count to 29. The team was led by Dr. Maryame El Moutamid of the Southwest Research Institute.

The count of inner moons stood at 11 until 2003, when Showalter and Dr. Jack Lissauer of NASA Ames discovered two moons, now named Mab and Cupid, using the Hubble Space Telescope. At the time, Hubble was the most powerful instrument available for detecting tiny moons orbiting close to one of the giant planets.

"JWST leaves Hubble in the dust," said Showalter. "It’s exciting to think about what additional discoveries might await us as JWST continues to study these distant worlds."

The small moon orbits about 56,000 kilometers (35,000 miles) from the planet’s center, between the orbits of the moons Ophelia and Bianca. It circles Uranus in less than half a day. Based on its brightness, the moon is estimated to be only six miles in diameter, too small to have been seen by Voyager 2 or the Hubble Space Telescope.

“No other planet has as many small inner moons as Uranus, and their complex inter-relationships with the rings hint at a chaotic history that blurs the boundary between a ring system and a system of moons,” said Tiscareno. “Moreover, the new moon is smaller and much fainter than the smallest of the previously known inner moons, making it likely that even more complexity remains to be discovered.” 

This new moon is the 14th of Uranus's small moons, which include Miranda, Ariel, Umbriel, Titania, and Oberon. Ultimately, the International Astronomical Union (IAU) will approve a name for this newly discovered moon.

This discovery gives scientists another target for studying the planet’s delicate system of rings and satellites.

Read more about this discovery here: https://science.nasa.gov/blogs/webb/2025/08/19/new-moon-discovered-orbiting-uranus-using-nasas-webb-telescope/