The hypothesis of planetary migration is tested by numerically integrating orbits of Trojan-type asteroids in the gravitational Ðeld of the Sun, the migrating parent planet, and at least one extra migrating planet. A linear model and an exponential model for migration are used. Migration speeds are deÐned by several total migration times for the linear model and by two di†erent timescales for t...

Recent results have shown that many of the known extrasolar planetary systems contain regions which are stable for massless test particles. We examine the possibility that Saturn-mass planets exist in these systems, just below the detection threshold, and attempt to predict likely orbital parameters for such unseen planets. To do this, we insert a Saturn-mass planet into the stable regions of t...

Thermochemical equilibrium and kinetic calculations for the trace gases CO, PH3, and SiH4 give three independent constraints on the water and total oxygen abundances of Saturn’s deep atmosphere. A lower limit to the water abundance of H2O/H2≥ (1.7 −0.4)×10 is given by CO chemistry while an upper limit of H2O/H2 ≤ (5.5 −2.5)×10 is given by PH3 chemistry. A combination of the CO and PH3 constrain...

We predict how a remote observer would see the brightness variations of giant planets similar to those in our Solar System as they orbit their central stars. We model the geometry of Jupiter, Saturn and Saturn’s rings for varying orbital and viewing parameters. Scattering properties for the planets and rings at wavelenghts 0.6-0.7 microns are assumed to follow these observed by Pioneer and Voya...

[1] Using a three-dimensional multifluid simulation, we demonstrate the importance of ion gyroradius and heavy ion effects when characterizing Titan’s plasma interaction with the Kronian magnetosphere. Ion gyroradius and heavy ion effects drastically change the mass loading and magnetic field draping at Titan. We find that the large ion gyroradius of picked up ionospheric species results in an ...