Dust Influx to Titan from Hyperion

Abstract

The outer part of the saturnian system, comprising four saturnian satellites — Phoebe, Iapetus, Hyperion, and Titan — is believed to excel in intricate mechanisms of production, evolution, and transport of dust between the involved moons. This paper is focused on the delivery of the dust material to Titan, with the neighboring Hyperion being the most effective dust supplier. Hypervelocity impacts of dust particles coming from Phoebe, as well as bombardments by interplanetary micrometeoroids should eject the surface material of Hyperion to the planetocentric space. We discuss the complex dynamics of the Hyperion ejecta, resulting from the interplay between the resonant gravity of Titan, solar radiation pressure, and plasma drag force. It is shown that unlike Hyperion, the motion of which is stabilized by a strong 4:3 mean motion resonance with Titan, a significant part of the Hyperion debris either is free of resonance initially or is liberated from the resonance during the subsequent dynamical evolution. These particles get in unstable orbits and experience multiple close approaches to Titan. Most of the grains larger than several μm in size finally collide with Titan. We show that the dust influx to Titan from Hyperion may exceed markedly the direct influx of interplanetary grains. It is argued that the influx of water-containing particles from Hyperion may play an important role in the chemistry of Titan’s atmosphere, making a significant contribution to the budget of the oxygen-bearing compounds.