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dc.contributor.authorAttree, Nicholas Oliver
dc.identifier.citationAttree, N.C. 2015. Collisional Features in Saturn's F Ring. Queen Mary University of London.en_US
dc.description.abstractThe role of physical collisions in shaping Saturn's F ring is explored using a mixture of dynamical theory, image analysis and computer simulations. The F ring is highly dynamic, being perturbed by the nearby moons, Prometheus and Pandora, and by a population of small bodies, whose presence is inferred by their influence on the ring, charged particle data and, occasionally, direct detection. Small-scale features, termed `mini-jets', are catalogued from images taken by the Imaging Science Subsystem of the Cassini spacecraft. More than 1000 are recorded, implying a population of 100 objects on nearby orbits, colliding with the ring at velocities of a few ms􀀀1. Many are seen to collide several times, forming repeated structures, and must have enough physical strength, or self-gravity, to survive multiple passages through the core. Larger features, called `jets', share a similar morphology. They are likely caused by a more distant population which collide at higher velocities ( 10 ms􀀀1) and are roughly an order of magnitude less common. Differential orbital motion causes jets to shear out over time, giving the ring its multi-stranded appearance. Jets have different orbital properties to mini-jets, probably because they result from multiple, overlapping collisions. Simulations using an N-body code show that the shape of collisional features depends heavily on the coefficient of restitution, particularly the tangential component. When both components are < 1 large objects merely sweep up small particles. Features like jets and mini-jets require large particles in both the target and impactor, as is the case for two similarly-sized aggregates colliding. A single population of aggregates is proposed, ranging from large, unconsolidated clumps, embedded in the core, through mini-jet-forming objects to the more distant, jet-forming colliders. Prometheus may be ultimately responsible for all of these features as its gravity can trigger clump formation as well as perturb particles.en_US
dc.description.sponsorshipScience and Technology Facilities Council (STFC)
dc.publisherQueen Mary University of London
dc.subjectBiological and Chemical Sciencesen_US
dc.subjectTetratrico Peptide Repeatsen_US
dc.titleCollisional Features in Saturn's F Ring.en_US
dc.rights.holderThe copyright of this thesis rests with the author and no quotation from it or information derived from it may be published without the prior written consent of the autho

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