Séminaire "Io as a present day « accessible » archetype of worlds undergoing extreme tidal heating" - Mathilde Kervazo (Doctorante au LPG)

Jeudi 11 Février 2021, 14:00 - 15:00
par Stéphanie BEAUNAY

Abstract : Tidal heating is one of the key drivers of the evolution of planetary worlds across the solar system and beyond, shaping their interior structure and geological activity. Io, the innermost of Jupiter’s satellites, is the most tidally deformed and heated world in the solar system, as evidenced by the prodigious endogenic power of about 100 TW. Io's interior processes manifest on the surface in a clearly detectable way, as extreme volcanic activity with hundreds of active volcanoes. This moon therefore provides a unique testbed for understanding tidally-induced endogenic activity and can serve as an archetype of rocky exoplanets and exomoons undergoing extreme tidal heating. A variety of models have been proposed to determine the mechanism at the origin of the huge tidal dissipation in Io’s interior. While a high concentration of melts below the lithosphere is in line to explain the heat production and the heat released by volcanic activity, the degree of melting of this subsurface layer, going from moderately molten mantle to fully liquid subsurface ocean, is still largely debated. This distribution of melt within the ionian mantle is a key question driving the ongoing and future exploration of Io. This is the main mission goal of the ’Io Volcano Observer’ (IVO), one of the Discovery finalists currently under consideration by NASA, planning to test these interior models via a set of geophysical measurements. One way to characterize it is through the tides. In this context, we re-evaluate the heat production in Io's interior, specifically quantifying the role of melt presence on both shear and bulk dissipation, and we calculate the tidal response of Io’s interior for various distribution of melt within the mantle, to discriminate them in future tidal monitoring.