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The determination of the structure of Saturn’s F ring by nearby moonlets

Nature volume 453, pages 739744 (05 June 2008) | Download Citation


Saturn’s narrow F ring exhibits several unusual features that vary on timescales of hours to years. These include transient clumps, a central core surrounded by a multistranded structure and a regular series of longitudinal channels associated with Prometheus, one of the ring’s two ‘shepherding’ satellites. Several smaller moonlets and clumps have been detected in the ring’s immediate vicinity, and a population of embedded objects has been inferred. Here we report direct evidence of moonlets embedded in the ring’s bright core, and show that most of the F ring’s morphology results from the continual gravitational and collisional effects of small satellites, often combined with the perturbing effect of Prometheus. The F-ring region is perhaps the only location in the Solar System where large-scale collisional processes are occurring on an almost daily basis.

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C.D.M., K.B., N.J.C., M.W.E. and G.A.W. are grateful to the UK Science and Technology Facilities Council for financial support. The success of the FMOVIE observations described in this paper is due to the invaluable assistance of M. Showalter and the Cassini VIMS team. The authors also wish to thank R. Nelson, D. McNeil, J. Burns and our other colleagues on the Cassini project for numerous discussions.

Author Contributions C.D.M. led the research, worked on image analysis and carried out the jet simulations. K.B. and M.W.E. wrote database and image analysis software, and contributed to image sequence design. Satellite and ring orbit analysis was done by N.J.C., as were the simulations of S/2004 S 6 encountering the F ring. Simulations of planar ring–satellite interactions were done by G.A.W. C.D.M., K.B., N.J.C., M.W.E., G.A.W. and S.C. all contributed to the theories discussed.

Author information


  1. Astronomy Unit, Queen Mary, University of London, Mile End Road, London E1 4NS, UK

    • Carl D. Murray
    • , Kevin Beurle
    • , Nicholas J. Cooper
    • , Michael W. Evans
    •  & Gareth A. Williams
  2. C. E. de Saclay, Université Paris 7, L’Orme de Merisiers, 91191 Gif-sur-Yvette Cedex, France

    • Sébastien Charnoz


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Corresponding author

Correspondence to Carl D. Murray.

Supplementary information

PDF files

  1. 1.

    Supplementary information

    The file contains Supplementary Figures 1-10 with Legends; Supplementary Tables 1-2 with Legends and Supplementary Video Legends 1-4.


  1. 1.

    Supplementary information

    The file contains Supplementary Video 1 showing animation of a massive S/2004 S 6 crossing a massless F ring core.

  2. 2.

    Supplementary information

    The file contains Supplementary Video 2 showing animation of a massive S/2004 S 6 crossing a massless F ring core viewed from two different angles.

  3. 3.

    Supplementary information

    The file contains Supplementary Video 3 showing a numerical simulation of the effect of a ~5 km-radius satellite on a circular, 50 km-wide ring of test particles followed over one orbital period and viewed in a rotating reference frame.

  4. 4.

    Supplementary information

    The file contains Supplementary Video 4 showing a numerical simulation of the effect of a conjunction between Prometheus and a ~5 km-radius satellite on a circular, 50 km-wide ring of test particles followed over one orbital period and viewed in a rotating reference frame.

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