The rings of Uranus

Abstract

ABSTRACTThe Uranian ring system consists of nine, narrow rings that have an average geometric albedo of 0.02. Since their discovery in 1977, the rings have been regularly observed with the technique of stellar occultations, which provides a spatial resolution of about 0.1 km in the positions of ring segments and about 4 km resolution in their structural details. The occultation data are well fitted by a kinematic model that describes the rings as ellipses, which are inclined to the equatorial plane of Uranus and precess due to harmonic terms in the Uranian potential field. The main characteristics of the Uranian ring system that need a confirmed theoretical explanation are: narrow rings, sharp edges, uniform orbital precession, origin of the eccentricities and inclinations, the structure of the e ring, the structure of the η ring and the origin of the ring system.