Chaotic diffusion in the outer solar system, and other topics

Abstract

We carried out extensive numerical orbit integrations to probe the long-term chaotic dynamics of the 2:3 (Plutinos) and 1:2 (Twotinos) mean motion resonances with Neptune. We derive maps of resonance stability measured both by time-averaged particle density and by mean dynamical diffusion rate, and investigate the effects of a massive perturber embedded in the resonance. We also investigate the population of Resonant Kuiper Belt Objects at 4 Gyr ago compared to the present, and discuss the implications for theories of Kuiper Belt origins. We have numerically investigated the long term dynamical behavior of known Centaurs. We find that their orbital evolution is characterized by frequent close encounters with the giant planets, with no significant long-term resonant behavior. Most of these Centaurs will escape from the inner solar system, while a fraction will enter the Jupiter-family comet (JFC) population and a few percent will impact a giant planet. We discuss the implications of our study for the spatial distribution of the actual Centaur population. Using numerical and analytical models, we investigate the ejection of water molecules from Europa's surface by sputtering, the subsequent evolution of their ballistic trajectories, and their re-deposition onto the surface as a water frost. We conclude that net deposition does occur under certain conditions, making sputtering erosion and re-deposition a plausible explanation for the observed color dichotomy between Europa's leading and trailing hemispheres. During Cassini's approach to Jupiter, a series of images was taken to search for any undiscovered satellites of Jupiter. Our analysis of these images indicates that no undiscovered satellites exist between 2.6 and 20 R(J) with inclination i < 1.6°, eccentricity e < 0.0002, diameter D > 15 km and albedo A > 0.1.