Coupled Thermal-Orbital Evolution of the Galilean Satellites

Io's volcanism and Europa's surface bear witness to the dynamics driven by tidal interactions of the Galilean moons with Jupiter. While Europa and Ganymede host subsurface oceans, which makes them prime candidates for habitability, tidal heating is unlikely to have been constant over the age of the Laplace resonance. In this talk I will revisit the coupled thermal - orbital evolution of the Galilean satellites using the astrometric and geophysical constraints obtained over the past years. The Juno mission has provided additional data about geodetic parameters and recent ground-based observations indicate that Io has been volcanically active for most of its history, with potentially higher activity at earlier times. We also apply lessons learned from the Saturn system, particularly informed by the Cassini mission, to investigate the possibility of ‘resonance locking’ as the dominant mechanism driving the orbital migration of Io. Our analysis shows that considering ‘resonance locking’ in the Jovian system could reveal new evolutionary paths with early tidal dissipation in Ganymede and periodic inward migration of Io. I will further discuss the implications for the structure and dynamics of Europa’s ice shell if ‘resonance’ locking is at play. Finally, I will outline how some of these hypotheses can be tested by the Europa Clipper mission.

Speaker: Gregor Steinbrügge, Jet Propulsion Laboratory

Room 350/372, or watch online (see weblink)