Orbital evolution of Saturn's satellites due to the interaction between the moons and massive Saturn's rings

Abstract

Saturn's mid-sized moons (satellites) have a puzzling orbital configuration with trapping in mean-motion resonances with every other pairs (Mimas-Tethys 4:2 and Enceladus-Dione 2:1). To reproduce their current orbital configuration on the basis of Crida & Charnoz's model of satellite formation from a hypothetical ancient massive rings, adjacent pairs must pass 1st-order mean-motion resonances without being trapped. The trapping could be avoided by fast orbital migration and/or excitation of the satellite's eccentricity caused by gravitational interactions between the satellites and the rings (the disk), which are still unknown. In our research, we investigate the satellite orbital evolution due to interactions with the disk through full N-body simulations. We performed global high-resolution N-body simulations of a self-gravitating particle disk interacting with a single satellite. We used $N\sim 10^5$ particles for the disk. Gravitational forces of all the particles and their inelastic collisions are taken into account. As a result, dense short-wavelength wake structure is created by the disk self-gravity and global spiral arms with $m\sim$ a few is induced by the satellite. The self-gravity wakes regulate the orbital evolution of the satellite, which has been considered as a disk spreading mechanism but not as a driver for the orbital evolution. The self-gravity wake torque to the satellite is so effective that the satellite migration is much faster than that was predicted with the spiral arms torque. It provides a possible model to avoid the resonance capture of adjacent satellite pairs and establish the current orbital configuration of Saturn's mid-sized satellites.

(6 pages, 4 figures, Accepted in A&A)

References in corpus (3)

• Formation of Regular Satellites from Ancient Massive Rings in the Solar System
• Long-term & large-scale viscous evolution of dense planetary rings
• Formation of Multiple-Satellite Systems From Low-Mass Circumplanetary Particle Disks

Cited by in corpus (4)

• A Framework for Characterizing Transmission Spectra of Exoplanets with Circumplanetary Rings
• Stability and detectability of exomoons orbiting HIP 41378 f, a temperate Jovian planet with an anomalously low apparent density
• Dynamical stability in the vicinity of Saturnian small moons. The cases of Aegaeon, Methone, Anthe and Pallene
• The Dynamical Viability of an Extended Jupiter Ring System