S/2025 U 1
Moon· orbits Uranus
S/2025 U 1 — moon of Uranus.
Open in 3D viewSee S/2025 U 1 in the live, interactive 3D map
Key facts
Radius
4.47 km
Orbit around Uranus
10.1 hours
0.42 Earth days
Science
Physical
- Radius (estimated)
- 4–5 km
- Sized from brightness assuming a dark (~0.04) surface — never resolved. The source gives a range of 8–10 km, not a single value.
Orbit around Uranus
- Distance from Uranus
- 57,844 km
- From JPL orbital elements
- Orbital period
- 10.08 hours
- From JPL orbital elements
- Eccentricity
- 0.039
- From JPL orbital elements
- Inclination to Uranus's Laplace plane
- 4.00 °
- From JPL orbital elements · The Laplace plane is the one a moon's orbit precesses about: close in it is the planet's equatorial plane, the plane of the rings, and further out it tilts toward the planet's own orbit.
Radiation & temperature
- Insolation
- 0.00265 S⊕ · 1/378 of the sunlight Earth receives
- Computed from the distance to the Sun (inverse-square; Earth's sunlight = 1), before any atmosphere.
Discovery & history
- Discovered
- February 2, 2025
- By
- M. El Moutamid, M. Hedman, M. Showalter, M. Tiscareno, I. de Pater, J. Lissauer, D. Souami
- Method
- Directly imaged
S/2025 U 1 was found by a team led by Maryame El Moutamid (Southwest Research Institute) in James Webb Space Telescope images taken on 2 February 2025 — ten long NIRCam exposures from a guest-observer programme — and announced on 19 August 2025 (CBET 5593), bringing Uranus's known moons to 29. It orbits about 56,000 km from the planet's centre, between Ophelia and Bianca. Its size is not measured: assuming it reflects light like its neighbours, it is roughly 10 km across. It has not yet been given a permanent name.
Images
No resolved image of this moon has been released: telescopes and passing spacecraft have recorded it only as a faint point of light.