Effects of neighbouring planets on the formation of resonant dust rings in the inner Solar System

Abstract

Context. Findings by the Helios and STEREO mission have indicated the presence of a resonant circumsolar ring of dust associated with Venus. Attempts to model this phenomenon as an analogue to the resonant ring of Earth – as a result of migrating dust trapped in external mean-motion resonances (MMRs) – have so far been unable to reproduce the observed dust feature. Other theories of origin have recently been put forward. However, the reason for the low trapping efficiency of Venus’s external MMRs remains unclear. Aims. Here we look into the nature of the dust trapping resonant phenomena that arise from the multi-planet configuration of the inner Solar System, aiming to add to the existent understanding of resonant dust rings in single planet systems. Methods. We numerically modelled resonant dust features associated with the inner planets and specifically looked into the dependency of these structures and the trapping efficiency of particular resonances on the configuration of planets. Results. Besides Mercury showing no resonant interaction with the migrating dust cloud, we find Venus, Earth, and Mars to considerably interfere with each other’s resonances, influencing their ability to form circumsolar rings. We find that the single most important reason for the weakness of Venus’s external MMR ring is the perturbing influence of its outer neighbour – Earth. In addition, we find Mercury and Mars to produce crescent-shaped density features, caused by a directed apsidal precession occurring in particles traversing their orbital region.