Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published February 1, 2018 | Published + Accepted Version
Journal Article Open

How Cassini can constrain tidal dissipation in Saturn


Tidal dissipation inside giant planets is important for the orbital evolution of their natural satellites. It is conventionally treated by parametrized equilibrium tidal theory, in which the tidal torque declines rapidly with distance, and orbital expansion was faster in the past. However, some Saturnian satellites are currently migrating outward faster than predicted by equilibrium tidal theory. Resonance locking between satellites and internal oscillations of Saturn naturally matches the observed migration rates. Here, we show that the resonance locking theory predicts dynamical tidal perturbations to Saturn's gravitational field in addition to those produced by equilibrium tidal bulges. We show that these perturbations can likely be detected during Cassini's proximal orbits if migration of satellites results from resonant gravity modes, but will likely be undetectable if migration results from inertial wave attractors or dissipation of the equilibrium tide. Additionally, we show that the detection of gravity modes would place constraints on the size of the hypothetical stably stratified region in Saturn.

Additional Information

© 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2017 October 16. Received 2017 October 13; in original form 2017 July 8. Published: 23 October 2017. We thank Peter Goldreich for his insightful suggestions and comments. We thank Phillip D. Nicholson and Luciano Iess for providing us information about the proximal orbits of Cassini. We thank Gordon Ogilvie for his clarification about his work on inertial waves, i.e. Ogilvie (2013). We thank Douglas N. C. Lin for his comments on inertial wave attractors. Jing Luan is supported by the Theoretical Astronomy Center and Center for Integrative Planetary Science at University of California at Berkeley. This research is funded in part by the Gordon and Betty Moore Foundation through Grant GBMF5076 and by the Simons Foundation through a Simons Investigator Award to Eliot Quataert.

Attached Files

Published - stx2714.pdf

Accepted Version - 1707.02519.pdf


Files (1.6 MB)
Name Size Download all
563.4 kB Preview Download
1.0 MB Preview Download

Additional details

August 19, 2023
October 18, 2023