Sharp Gap Edges in Dense Planetary Rings

  • One of the most intriguing facets of Saturn's rings are the sharp edges of gaps in the rings where the surface density abruptly drops to zero. This is despite of the fact that the range over which a moon transfers angular momentum onto the ring material is much larger. Recent UVIS-scans of the edges of the Encke and Keeler gap show that this drop occurs over a range approximately equal to the rings' thickness. Borderies et al. show that this striking feature is likely related to the local reversal of the usually outward directed viscous transport of angular momentum in strongly perturbed regions. In this article we revise the Borderies et al. model using a granular flow model to define the shear and bulk viscosities, ν and ζ, and incorporate the angular momentum flux reversal effect into the axisymmetric diffusion model we developed for gaps in dense planetary rings. Finally, we apply our model to the Encke and Keeler division in order to estimate the shear and bulk viscosities in the vicinity of both gaps

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Author details:Fabio M. GrätzORCiD, Martin SeißORCiD, Jürgen Schmidt, Joshua Colwell, Frank SpahnORCiDGND
Title of parent work (English):The astrophysical journal : an international review of spectroscopy and astronomical physics
Subtitle (English):an Axisymmetric Diffusion Model
Publisher:IOP Publ. Ltd.
Place of publishing:Bristol
Publication type:Article
Date of first publication:2019/02/20
Completion year:2019
Release date:2021/04/07
Tag:celestial mechanics; diffusion; hydrodynamics; planets and satellites: rings; scattering
Page number:11
Funding institution:Studienstiftung des deutschen Volkes; Deutsches Zentrum fur Luft- und RaumfahrtHelmholtz AssociationGerman Aerospace Centre (DLR) [OH 1401]
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie
DDC classification:5 Naturwissenschaften und Mathematik / 52 Astronomie / 520 Astronomie und zugeordnete Wissenschaften
Peer review:Referiert