Evection resonance in Saturn's coorbital moons in the context of exoplanetary systems

C. A. GIUPPONE; X. SAAD OLIVERA; F ROIG

Santiago de Chile

Workshop; Diversis mundi: The Solar System in an Exoplanetary context; 2018

ESO

In the Solar System is widely accepted that most distant region of stability for prograde and retrograde satellites is associated with the evection resonance, produced as a consequence of the Sun as a perturber. At this region, the critical angle librates for moderate values of eccentricities, compatible with irregular satellites characteristics. It is important to note that the oblateness of a planet also produces a region of evection resonance at innermost regions of satellites of giant planets. The moons of Saturn exhibit a complex dynamical architecture, and coorbital configuration has a high occurrence in certain region near to the planet. Is our intention to study the location of evection resonance for Saturn and compare the dynamic for a single moon and a pair of coorbital mooons. We study the location of evection resonance for single satellites with N-body integrations for single moon systems. Then we identify the regions of evection for coorbital moons. We develop an analytical model applied to the trojan case based on a classical averaged expansion of the disturbing function that considers a mix set of canonical coordinates. Finally we use numerical methods to test the validity of the models. In Saturn we find two important and unconnected regions where the evection rules the dynamics. The inner evection resonance is present near two Saturn radius and tidal evolution of satellites demonstrate that while evolve from inner to outer regions coorbital companions are exited and the more massive companion only survived. On the other hand, at the exterior evection resonance region the coorbital configurations present small diffusion that finally breaks the resonance.