Planetary Science and Exploration Seminar, Gregor Steinbrügge- "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.

Gregor Steinbrügge received his M.S. degree in physics from the Free University of Berlin, Germany, in 2013 and completed his Ph.D. at the Institute of Geodesy and Geoinformation Science of the Technical University of Berlin, Germany, in 2018. His thesis on tidal interactions across the Solar System was completed in collaboration with the Institute of Planetary Research at the German Aerospace Center (DLR). He is a Research Scientist at the Jet Propulsion Laboratory and the Investigation Scientist for REASON (Radar for Europa Assessment and Sounding: Ocean to Near-surface). He is also a Co-Investigator on the BepiColombo Laser Altimeter (BELA) and on the Ganymede Laser Altimeter (GALA) aboard Juice, and a member of the VenSAR science team on ESA's EnVision mission. His research focuses on tidal interactions of planetary bodies in our Solar System, ice geophysics, radar and laser geodesy, and the development of innovative mission instrumentation.

Speaker suggested reading: Hussmann, H., & Spohn, T. (2004). Thermal-orbital evolution of Io and Europa. Icarus, 171(2), 391–410. https://doi.org/10.1016/j.icarus.2004.05.020