Sometimes You Just Can't Put a Ring on It: Setting Constraints on Rings around Moons from Magnetic Fields

TL;DR

This paper explores how planetary magnetic fields influence the stability of potential rings around moons, revealing that magnetic effects can prevent ring formation by de-orbiting charged particles.

Contribution

It introduces a new analytical and numerical framework to constrain the existence of moon rings based on magnetic field interactions, a novel approach in planetary ring studies.

Findings

Magnetic fields induce electric fields that destabilize charged ring particles.

Charged grains can be de-orbited on short timescales due to magnetic perturbations.

Magnetic effects significantly limit the stability of potential moon rings.

Abstract

All four giant planets and several minor bodies in the Solar System host rings. However, rings around moons have yet to be observed. A host planet can produce magnetic fields that affect its moons, adding a wealth of dynamical phenomena that could shape the properties of such ring systems. In this study, we investigate constraints on the stability of circumsatellitial rings (CSRs) under the effect of magnetic fields originating from the host planet, using both analytical and numerical methods. We find that the electric field induced by the rotation of the ambient planetary magnetosphere constitutes a significant perturbation on charged grains in CSRs. We demonstrate that this effect can de-orbit sufficiently charged grains on short timescales, providing a novel approach to constrain the properties of CSRs.