Scaling laws to quantify tidal dissipation in star-planet systems

TL;DR

This paper develops a local analytical model to quantify tidal dissipation in fluid star-planet systems, emphasizing the role of internal structure and resonant gravito-inertial waves in energy dissipation.

Contribution

It introduces a new local model for tidal gravito-inertial waves that analytically links dissipation to fluid properties and internal structure, advancing understanding of tidal evolution.

Findings

Derived scaling laws for tidal dissipation based on fluid parameters.

Identified the influence of resonant frequencies on energy dissipation.

Discussed implications for star-planet system evolution.

Abstract

Planetary systems evolve over secular time scales. One of the key mechanisms that drive this evolution is tidal dissipation. Submitted to tides, stellar and planetary fluid layers do not behave like rocky ones. Indeed, they are the place of resonant gravito-inertial waves. Therefore, tidal dissipation in fluid bodies strongly depends on the excitation frequency while this dependence is smooth in solid ones. Thus, the impact of the internal structure of celestial bodies must be taken into account when studying tidal dynamics. The purpose of this work is to present a local model of tidal gravito-inertial waves allowing us to quantify analytically the internal dissipation due to viscous friction and thermal diffusion, and to study the properties of the resonant frequency spectrum of the dissipated energy. We derive from this model scaling laws characterizing tidal dissipation as a function of fluid parameters (rotation, stratification, diffusivities) and discuss them in the context of star-planet systems.