On The Linear Damping Relation For Density Waves In Saturn'S Rings

Keywords

planets and satellites: rings

Abstract

We revisit the equation for viscous damping of density waves derived from linearized theory and show that the damping is not only determined by the magnitudes of shear and bulk viscosity. Modifications arise from the dependence of the viscosity on the ring's surface mass density. This was noted more than 30 years ago by Goldreich & Tremaine (1978b). Still, to date the consequences have not been explored. In the literature these terms have been neglected throughout when fitting the rings' viscosity from observations of wave damping. Therefore, one must suspect that these viscosities, as well as the dispersion velocities inferred from them, suffer from systematic bias, which might be small or significant, depending on the local conditions in the ring. We show that the modified damping formula, to linear order, is related to the stability threshold for viscous overstability and argue that the appearance of density waves may be altered by this instability.

Publication Date

6-10-2016

Publication Title

Astrophysical Journal

Volume

824

Issue

1

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.3847/0004-637X/824/1/33

Socpus ID

84976433870 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84976433870

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