New moon discovered around Uranus by JWST team

Using NASA’s James Webb Space Telescope (JWST), scientists have discovered a tiny, previously unknown moon orbiting Uranus

This new find increases the number of known Uranian moons to 29 and offers new insights into the dynamics of this often-overlooked ice giant.

The discovery was made by a team led by Dr. Maryame El Moutamid from the Southwest Research Institute (SwRI). The small satellite, currently designated S/2025 U 1, was detected in a series of 10 long-exposure images captured by JWST’s powerful Near-Infrared Camera. The find is part of JWST’s guest observer program, which allows scientists to submit proposals for specific observations using the telescope’s advanced instruments.

Small Uranian moon discovered to date

S/2025 U 1 is estimated to be about six miles (10 kilometers) in diameter, making it the smallest moon ever found orbiting Uranus. Due to its small size and faint brightness, it had remained undetected in earlier surveys, including those by Voyager 2, which flew by Uranus in 1986.

The new moon’s position was identified near the planet’s inner rings, nestled between the orbits of two other known moons, Ophelia and Bianca. Ophelia is approximately 13 miles (43 km) wide, while Bianca is larger and elongated, measuring about 40 by 29 miles (64 by 46 km). S/2025 U 1 lies roughly 35,000 miles (56,250 kilometers) from Uranus’ center, traveling within the planet’s equatorial plane.

This discovery adds to the legacy of space exploration around Uranus, a planet that has only been visited once. During that flyby, Voyager revealed the planet’s ring system, atmospheric details, and several new moons. However, its instruments were not sensitive enough to detect moons as small as S/2025 U 1.

Now, with the advanced imaging capabilities of JWST, astronomers are gaining new opportunities to revisit and expand our understanding of the outer solar system. The detection of such a small object so close to the planet’s inner ring system shows the precision and reach of JWST’s technology.

Uranus

Uranus, the seventh planet from the Sun, is known for its extreme axial tilt it essentially rolls around the Sun on its side. The planet’s atmosphere is composed primarily of hydrogen, helium, and methane, which gives it a cyan hue.

Its moons are unique in their naming tradition. Unlike the mythological names given to most planetary satellites, Uranus’ moons are named after characters from the works of William Shakespeare and Alexander Pope. These include its five major moons, Titania, Oberon, Umbriel, Ariel, and Miranda and smaller ones discovered over the years.

With the latest moon still holding a provisional designation, astronomers are now considering appropriate names that follow the planet’s literary naming convention. The discovery team is exploring Shakespearean and Popean characters that could suitably reflect the newest member of Uranus’ growing moon family.