EES Seminar Series - Dr. Michaela Walterová

"Tidal evolution of rocky exoplanets"

Dec 9, 2022 at - | Hayden Hall 358

Geoscience Colloquium

The Department of Earth & Environmental Science

University of Pennsylvania

Invites you to attend a EES Seminar Series

Friday, December 9th - 3:00 PM


Dr. Michaela Walterová

Faculty of Mathematics and Physics

Charles University



The long-term evolution of rocky exoplanets orbiting close to their host star is strongly influenced by tides. Periodic tidal loading results in time-varying deformation, which is---in realistic materials---accompanied by energy dissipation. Tidal dissipation has two important consequences:

First, the produced heat might enhance the thermal evolution of the planet and even trigger structural changes in its interior, such as the formation of a subsurface magma ocean. Second, the gradual loss of mechanical energy fuels rotational and orbital evolution, i.e., it drives the planet into spin-orbit resonances and decreases the radius of its orbit.

In this talk, I will focus on modeling and coupling the effects introduced above. After a brief overview of the tidal theory and of the ensemble of known rocky exoplanets, we will take a look at the stability of different spin-orbit resonances (such as the 3:2 resonance of planet Mercury), long-term orbital evolution, and the parameter dependence of tidal dissipation. We will also discuss the effect of tidal dissipation on thermal evolution as well as the feedback between internal, orbital, and rotational dynamics. The modeling approach will be specifically illustrated on the example of the closest exoplanet Proxima Centauri b, which orbits in the conventional habitable zone of its host star and is of special interest for astrobiology.