Understanding tidal dissipation in gaseous giant planets : the respective contributions of their core and envelope

TL;DR

This paper investigates how both the core and envelope of gaseous giant planets contribute to tidal dissipation, highlighting the importance of considering both regions for understanding planetary evolution.

Contribution

It provides a detailed computation of the separate tidal dissipation contributions from the core and envelope based on their internal structures.

Findings

Both core and envelope significantly contribute to tidal dissipation.

The dissipation depends on core size and mass.

Considering both regions is essential for accurate models.

Abstract

Tidal dissipation in planetary interiors is one of the key physical mechanisms that drive the evolution of star-planet and planet-moon systems. New constraints are now obtained both in the Solar and exoplanetary systems. Tidal dissipation in planets is intrinsically related to their internal structure. In particular, fluid and solid layers behave differently under tidal forcing. Therefore, their respective dissipation reservoirs have to be compared. In this work, we compute separately the contributions of the potential dense rocky/icy core and of the convective fluid envelope of gaseous giant planets, as a function of core size and mass. We then compare the associated dissipation reservoirs, by evaluating the frequency-average of the imaginary part of the Love numbers $k^2_2$ in each region. We demonstrate that in general both mechanisms must be taken into account.