Characterization of Icy Moon Hydrospheres Through Joint Inversion of Gravity and Magnetic Field Measurements

Several bodies in the outer solar system are believed to host liquid water oceans underneath their icy surfaces. Knowledge of the hydrosphere properties is essential for understanding and assessing their habitability. We introduce a methodology based on Bayesian inference that enables a robust characterization of the hydrosphere through the combination of gravity and magnetic induction data. The interior models retrieved are consistent with the geophysical observations, leading to probability distributions for the relevant interior properties. We apply this joint inversion approach to constrain Europa's hydrosphere with gravity and magnetic field measurements acquired by the Galileo mission. Our results indicate that the combination of these datasets allows simultaneous constraints on the ice shell and ocean thickness, enhancing our knowledge of the hydrosphere structure. This methodology is valuable for synergistic interior science investigations of several missions in development or in planning, including Europa Clipper, JUICE and the Uranus Orbiter and Probe. We developed a technique to combine measurements of gravity and magnetic field that improves the characterization of icy moon hydrospheres We applied this joint inversion to constrain Europa's ice and ocean thicknesses with gravity and magnetic induction data from Galileo Our results demonstrate that the joint inversion of these observations allows us to better understand the hydrosphere's structure