THE MAJOR MOONS OF URANUS AND NEPTUNE

In this talk we will review what is known of the geology of the 5 largest Uranian satellites (Oberon, Titania, Umbriel, Ariel, and Miranda) and Neptune’s large satellite Triton. Virtually everything we know of these worlds comes from the 1986 and 1989 encounters of Voyager 2. These 5 Uranian satellites fall within the same size and density range as the middle sized icy satellites of Saturn. Cassini observations of these Saturnain satellites inform our evolving understanding of the major Uranian satellites. Some, such as Miranda and Ariel, show extensive modification of their surfaces by endogenic processes, which may be analogous to processes operating on Saturn’s moons such as Enceladus and Dione. Triton, Neptune’s only large satellite, is a captured KBO, whose post-capture orbital evolution has powered, and may still be driving, massive resurfacing. Triton has the best-known examples of cryo-volcanism in the Solar System. Triton also sports nitrogen geysers, which may be energized by solar heating. Triton is approximately the same size and density as Pluto, and may be our best preview of Pluto prior to the arrival of New Horizons in 2015.