EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

The influence of a stratified core on Mercury's librations

Fleur Seuren1,2, Santiago Andres Triana1, Jérémy Rekier1, Tim Van Hoolst1,2, and Véronique Dehant1
Fleur Seuren et al.
  • 1Royal Observatory of Belgium, Uccle, Belgium
  • 2Institute of Astronomy, KU Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium

Earth-based measurements of Mercury's libration amplitude have been used previously to establish the existence of Mercury's liquid core and to estimate its size. However these previous works have not yet taken into account the internal core flows that can be induced by rotational variations such as librations. In the present study, we use a numerical linear model to investigate the effect that these internal flows might have on Mercury's libration amplitude and other observables. In particular we find that the inclusion of a stably stratified layer at the top of the core – the existence of which has been suggested by thermal evolution and numerical dynamo models – in most cases prohibits the transmission of any motion from the top of the core to its deeper parts and vice versa.

How to cite: Seuren, F., Triana, S. A., Rekier, J., Van Hoolst, T., and Dehant, V.: The influence of a stratified core on Mercury's librations, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12178,, 2022.


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