Umbriel is the third-largest moon of Uranus. It was discovered on October 24, 1851, by William Lassell at the same time as neighboring moon Ariel. It was named after a character in Alexander Pope's 1712 poem The Rape of the Lock. From Wikipedia
Ultraviolet measurements attribute unexpected dark, red hues on the leading hemispheres of Uranus’s outer moons to dust from irregular satellites, upending expectations of magnetospheric effects
