Orbits of the Irregular Satellites of Uranus and Neptune

Abstract

Abstract We report on an ephemerides update for the irregular satellites of Uranus and Neptune, including Nereid. Our data set contains ground-based and Voyager 2 position measurements of the satellites. Some of the new observations were reduced with respect to the GAIA star catalog and represent high-quality, modern astrometry. The orbital fits are based on the numerically integrated equations of motion. We summarized results in terms of state vectors, orbital uncertainties, and mean elements. A large number of the irregulars have not been followed up in over a decade, and our study shows that their orbits still contain significant uncertainties.