Rivoldini, Attilio ; Tosi, Nicola ; Lécaille, Manon ; Van Hoolst, Tim ; Trinh, Anthony ; Baland, Rose-Marie ; Yseboodt, Marie ; Xiao, Haifeng

Poster presented at Unravelling the magnetic histories of Earth and other terrestrial objects, London, UK on 2026-09-14

Abstract: Interior structure inferences for Mercury based on geodetic data can be strongly affected by prior assumptions about the detailed thermal structure of the core. In particular, the presence of a conductive, thermally stratified layer in the upper core (CTSL) is often neglected, although it directly affects the core temperature profile and, consequently, inferences about core composition and inner-core radius. The upper CTSL is a key component of numerical dynamo simulations that can explain important features of Mercury’s magnetic field. Additional support for a CTSL also comes from thermal evolution studies that use constraints on dynamo activity in the core. In this study, we assess how assumptions about core composition, the present-day thermal state, and the CTSL affect Mercury’s annual libration amplitude, long-period libration, obliquity, and tidal Love numbers. To determine the present-day thermal state, we use results from whole-planet thermal evolution simulations that are consistent with assumptions about core composition and constrained by crustal thickness, radial contraction, and past and present dynamo activity.

Funding: 3PRODPLANINT/3PRODPLANINT/3PRODPLANINT