Leveraging the Gravity Field Spectrum for Icy Satellite Interior Structure Determination: The Case of Europa with the Europa Clipper Mission

• Published in: The planetary science journal 2024-02, Vol.5 (2), p.45
• Main Authors: Cascioli, G., Mazarico, E., Dombard, A. J., Nimmo, F.
• Format: Article
• Language: English
• Subjects: Europa; Galilean satellites; Hydrosphere; Lunar and Planetary Science and Exploration; Markov chain Monte Carlo; Planetary interior; Planetary science
• ISSN: 2632-3338; 2632-3338
• DOI: 10.3847/PSJ/ad1933

Understanding the interior structures of icy moons is pivotal for addressing their origins and habitability. We introduce an approach employing the gravity field spectrum as an additional constraint for the inversion of differentiated icy bodies' interior structures. After developing the general methodology, we apply it to Europa, utilizing the predicted measurement capability of NASA's Europa Clipper mission, and we prove its effectiveness in resolving key geophysical parameters. Notably, we show that using the gravity field spectrum in combination with the mass and moment of inertia of the body allows us to estimate, depending on the considered end-member interior structure, the hydrosphere thickness with 4–20 km uncertainty and reliably determine the seafloor maximum topographic range and elastic thickness to within 100–600 m and 5–15 km, respectively, together with the power–degree relationship of the seafloor topography. We also show that the proposed method allows us to determine the density of the silicate mantle and the radius of the core to within 0.25 g cc−1 and 50 km, respectively.