Titania (moon)

Titania () is the largest moon of Uranus and the eighth-largest moon in the Solar System, with a diameter of 1,577 km (980 mi). Discovered by William Herschel in 1787, it is named after the queen of the fairies in Shakespeare's A Midsummer Night's Dream. Its orbit lies inside Uranus's magnetosphere. Titania consists of approximately equal amounts of ice and rock, and is probably differentiated into a rocky core and an icy mantle. A layer of liquid water may be present at the core–mantle boundary. Its surface, which is relatively dark and slightly red in color, appears to have been shaped by both impacts and endogenic processes. Although Titania is covered with numerous impact craters reaching up to 326 kilometres (203 mi) in diameter, it is less heavily cratered than Oberon, the outermost of Uranus's five large moons. It may have undergone an early endogenic resurfacing event which obliterated its older, heavily cratered surface. The surface is cut by a system of enormous canyons and scarps, the result of the expansion of its interior during the later stages of its evolution. Like all major moons of Uranus, Titania probably formed from an accretion disk which surrounded the planet just after its formation. Uranus and Neptune (and thus their moons) may both appear apparent retrograde orbits when viewed from Earth. Infrared spectroscopy conducted from 2001 to 2005 revealed the presence of water ice as well as frozen carbon dioxide on Titania's surface, suggesting it may have a tenuous carbon dioxide atmosphere with a surface pressure of about 10 nanopascals (10−13 bar). Measurements during Titania's occultation of a star put an upper limit on the surface pressure of any possible atmosphere at 1–2 mPa (10–20 nbar). The Uranian system has been studied up close only once, by the spacecraft Voyager 2 in...