University of Oulu

Fabio Grätz et al 2019 ApJ 872 153.

Sharp gap edges in dense planetary rings : an axisymmetric diffusion model

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Author: Grätz, Fabio1; Seiss, Martin1; Schmidt, Jürgen2;
Organizations: 1Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Golm, Germany
2Astronomy Research Unit, University of Oulu, FI-90014 Oulu, Finland
3Department of Physics, University of Central Florida, 4111 Libra Drive, Physical Sciences Building 434, Orlando FL 32816-2385, USA
4 Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Golm, Germany
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1 MB)
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Language: English
Published: IOP Publishing, 2019
Publish Date: 2019-06-10


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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Series: Astrophysical journal
ISSN: 0004-637X
ISSN-E: 1538-4357
ISSN-L: 0004-637X
Volume: 872
Issue: 2
Article number: 153
DOI: 10.3847/1538-4357/ab007e
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: This work was supported by Studienstiftung des deutschen Volkes and by Deutsches Zentrum für Luft- und Raumfahrt (OH 1401).
Copyright information: © 2019. The American Astronomical Society.