Uranus XXVIII (previously known as S/2025 U 1) is a small moon of Uranus, with an estimated diameter between . It was the 29th moon identified in the Uranian system. The discovery was announced in August 2025 by a team of astronomers led by Maryame El Moutamid, who found the moon in James Webb Space Telescope NIRCam images taken on 2 February 2025.
The moon orbits about from the center of Uranus (between the orbits of Ophelia and Bianca) with an orbital period of . Like the other inner moons of Uranus, it follows a nearly circular orbit along Uranus's equatorial plane. Due to its small size, it appears extremely faint with a near-infrared (H-band) apparent magnitude of 25.5âÂÂtoo faint to be seen by the Hubble Space Telescope and the Voyager 2 spacecraft.
Uranus XXVIII (or ) is the permanent Roman numeral designation of this unnamed moon, given by the International Astronomical Union (IAU) Minor Planet Center on 24 March 2026. Previously, it was known as , the temporary provisional designation given when it was announced. By convention, the moons of Uranus are named after characters from the plays of William Shakespeare and Alexander Pope. A proper name will be given once it is approved by the IAU. Co-discoverer Mark R. Showalter has stated in a 2025 New Scientist article that "there have been discussions [of a name for the moon] but no shortlist as yet."
Uranus XXVIII is the 14th known member of Uranus's inner moons, which are small moons that orbit interior to the planet's five largest moons (Miranda, Ariel, Umbriel, Titania, and Oberon). Uranus XXVIII follows a nearly circular orbit around Uranus's equatorial plane, at a distance of from the planet's center with an orbital period of . Uranus XXVIII is located outside the edge of Uranus's inner ring system, between the orbits of Ophelia and Bianca. The nearly circular orbit of Uranus XXVIII suggests that it formed near its current location, according to El Moutamid.