Prospero (moon)
Prospero, also known as , is one of the largest retrograde irregular satellites of Uranus.
Discovery and Naming
Prospero was discovered on 18 July 1999 by the astrophysicist Matthew Holman and his team, and given the provisional designation S/1999 U 3.Confirmed as Uranus XVIII, it was named after the sorcerer Prospero in William Shakespeare's play The Tempest.
Orbit
Prospero orbits Uranus at an average distance of 16,256,000 km, in 1978 days, at an inclination of about 152° to the ecliptic, in a retrograde direction and with a high eccentricity of 0.445. The orbital elements are continuously changing due to solar and planetary perturbations.Physical characteristics
Prospero's estimated diameter is 50 kilometers, assuming an albedo of 4%.The satellite appears neutral in visible light, similar to Setebos.
Measurements of Prospero's light curve by the Kepler Space Telescope indicate that its rotation period is about 7 hours and 8.76 min, which makes it one of the fastest-rotating moons in the Solar System.