Jupiter's Dynamical Love Number

TL;DR

This paper explains the observed deviation in Jupiter's tidal Love number by calculating its dynamical response, highlighting the roles of planetary oscillation modes and interior stratification.

Contribution

It introduces a simple, efficient method to compute Jupiter's dynamical Love number, accounting for mode contributions and interior stratification effects.

Findings

Dynamical Love number is lower than hydrostatic value by 4%.

Inertial modes have negligible impact on Love number.

Strong stratification can significantly affect Love number measurements.

Abstract

Recent observations by the {\it Juno} spacecraft have revealed that the tidal Love number $k_2$ of Jupiter is $4\%$ lower than the hydrostatic value. We present a simple calculation of the dynamical Love number of Jupiter that explains the observed "anomaly". The Love number is usually dominated by the response of the (rotation-modified) f-modes of the planet. Our method also allows for efficient computation of high-order dynamical Love numbers. While the inertial-mode contributions to the Love numbers are negligible, a sufficiently strong stratification in a large region of the planet's interior would induce significant g-mode responses and influence the measured Love numbers.