OBSERVATIONS AND ANALYSIS OF MUTUAL EVENTS BETWEEN THE URANUS MAIN SATELLITES

摘要

Every 42 years, the Earth and the Sun pass through the plane of the orbits of the main satellites of Uranus.In these occasions, mutual occultations and eclipses between these bodies can be seen from the Earth. Thecurrent Uranus equinox from 2007 to 2009 offers a precious opportunity to observe these events. Here, wepresent the analysis of five occultations and two eclipses observed from Brazil during 2007. For the reductionof the CCD images, we developed a digital coronagraphic method that removed the planet's scattered lightaround the satellites. A simple geometric model of the occultation/eclipse was used to fit the observed lightcurves. Dynamical quantities such as the impact parameter, the relative speed, and the central time of theevent were then obtained with precisions of 7.6 km, 0.18 km s-1 , and 2.9 s, respectively. These resultscan be further used to improve the parameters of the dynamical theories of the main Uranus satellites.