Rivoldini, Attilio ; Beuthe, Mikael ; Van Hoolst, Tim ; Wieczorek, Mark ; Baland, Rose-Marie ; Dehant, Véronique ; Folkner, William ; Gudkova, Tamara ; Le Maistre, Sébastien ; Péters, Marie-Julie ; Yseboodt, Marie ; Zharkov, Vladimir

Poster presented at EGU General Assembly, EGU2019, 7-19 April, 2019 in Vienna, Austria on 2019-04-12

Abstract: Mars’ tidally forced nutation can be resonantly amplified owing to a rotational normal mode called the Free CoreNutation (FCN) which exists because the mantle and fluid part of the core can have a relative rotational motion.The period of the FCN and the amplitude of the nutation depend on the moments of inertia of the mantle and core,as well as on the deformation of the planet due to rotation rate variations and tidal forcing. One of the goals of theRISE experiment on InSight and of the future LaRa experiment on ExoMars 2020 is to infer the core radius ofMars by measuring nutation. Precise core radius determination from the FCN period requires knowledge of thecore shape. Here we study how non-hydrostatic core shape models affect the FCN and discuss to what extent theshape of the core could be inferred if its radius were known.

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Funding: ESA/PRODEX/PlanetInt ESA/PRODEX/LaRa