Is it necessary to go beyond the ponctual mass approximation for tidal perturber in close systems?

TL;DR

This paper examines whether the point-mass approximation is sufficient for modeling tidal interactions in very close star-planet and satellite systems, using a formalism that accounts for extended body effects.

Contribution

It introduces a formalism to evaluate the importance of extended body effects in tidal interactions for close systems, challenging the common point-mass approximation.

Findings

Point-mass approximation may be insufficient for very close systems.

Extended body effects can significantly alter tidal interaction outcomes.

The formalism provides a more accurate modeling approach for close system dynamics.

Abstract

With the discoveries of very close star-planet systems with planet orbiting sometimes at several star radius but also with well-known situations in our solar system where natural satellites are very close to their parent planet the validity of the ponctual mass approximation for the tidal perturber (respectively the parent star or planet when we study the close planet or natural satellite dynamics) has to be examined. In this short paper, we consider this problematic using results coming from a complete formalism that allows to treat the tidal interaction between extended bodies. We focus on its application to a simplified configuration.