Dynamical tides in Jupiter and other rotationally flattened planets and stars with stable stratification

TL;DR

This paper presents a numerical method to compute the dynamical tidal response of rapidly rotating, oblate stars and planets with realistic internal structures, revealing resonances that explain observed tidal behaviors.

Contribution

The authors develop a new numerical approach to analyze dynamical tides in oblate, rotating celestial bodies with complex internal stratification, including Jupiter models.

Findings

Resonances involving mixed gravito-inertial and inertial waves are significant.

Rotational flattening affects the tidal response and resonance spectrum.

The model explains discrepancies in Jupiter's observed tidal response.

Abstract

We develop a numerical method for directly computing the dissipative dynamical tidal response of rapidly rotating, oblate stars and gaseous planets with realistic internal structures. Applying these calculations to neutrally and stably stratified polytropes, we identify the most relevant resonances in models with rotation rates up to nearly the mass-shedding limit. We then compute the dynamical tidal response for Jupiter interior models including both stably stratified and convective regions. These calculations show that resonances involving mixed waves with both gravito-inertial and purely inertial character are capable of explaining a discrepancy between observations and hydrostatic calculations of Jupiter's response to tidal forcing by Io. This result contrasts with recent work that excluded Jupiter's rotational flattening, and opens the door to resonances involving a wider range of internal oscillation modes than previously considered.