(1) Space Research Centre, Warsaw, Poland, (marekb@cbk.waw.pl)
(2) St. Petersburg University, St. Petersburg, Russia, (krivov@aispbi.spb.su)
It is argued that Hyperion, an irregularly-shaped, distant Saturn's satellite, may act as a reasonably effective source of dust in the saturnian system. Several mechanisms (e.g. hypervelocity impacts of interplanetary grains or dust particles coming from the outermost saturnian moon Phoebe) should produce impact ejecta from Hyperion's surface, an appreciable share of which would escape into the planetocentric orbits initially close to that of Hyperion. Many of the particles would remain locked in a strong 4:3 mean motion resonance with Titan and form a stable dust belt around Hyperion's orbit. However, initial speeds of order 100 m/s (measured at the boundary of Hyperion's action sphere) are sufficient to break down the resonance. Solar radiation pressure and plasma drag forces are also capable of destroying the resonant locking; this is the case for particles smaller than several tens of micrometers. Each of the three mechanisms would place dust particles into unstable orbits which experience multiple close approaches to Titan. Some of the grains will then collide with Titan, others will spread into the inner part of the Saturnian system, still others may escape from Saturn's gravity and contribute to the interplanetary cloud. Small particles (with radii less than 2 to 3 micrometers) will swiftly collide with Saturn due to strong radiation pressure perturbations. Using numerical integrations, we performed a statistical study of the grain trajectories to determine the probabilities of various scenarios and to construct a relative (i.e. normalized to unit source flux) distribution of dust. Of-order estimates of the dust influx to Titan are also made.