First detection of Lithium in Mercury's exosphere

Daniel Schmid; Helmut Lammer; Martin Volwerk; Fabian Weichbold; Manuel Scherf; Ali Varsani; Owen Wyn Roberts; Cyril Simon-Wedlund; Ferdinand Plaschke

doi:https://doi.org/10.5194/egusphere-egu24-16068

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EGU24-16068, updated on 09 Mar 2024

https://doi.org/10.5194/egusphere-egu24-16068

EGU General Assembly 2024

© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

First detection of Lithium in Mercury's exosphere

Daniel Schmid¹, Helmut Lammer¹, Martin Volwerk¹, Fabian Weichbold¹, Manuel Scherf¹, Ali Varsani¹, Owen Wyn Roberts², Cyril Simon-Wedlund¹, and Ferdinand Plaschke³

Daniel Schmid et al.

¹Space Research Institute (IWF) Graz, Graz, Austria (daniel.schmid@oeaw.ac.at)
²Department of Physics, Aberystwyth University, UK
³IGEP, TU Braunschweig, Germany

Mercury has an extended exosphere that consists of various species. Based on theoretical considerations, the existence of Lithium (Li) in the exosphere around Mercury is predicted to be less than 5x10⁷ cm^-2. Because these density values are well below the detection limits of remote observation instruments on board past missions, Li has never been directly observed. Here we show the first on-site determined altitude-density profile of atomic Li₇, derived from in-situ magnetic field observations by the MESSENGER spacecraft. The results suggest that the source of Li at Mercury is most likely meteoritic ablation. The findings will help to interpret the remote observations of Mercury's exosphere that will be realized in the near future by the BepiColombo mission.

How to cite: Schmid, D., Lammer, H., Volwerk, M., Weichbold, F., Scherf, M., Varsani, A., Roberts, O. W., Simon-Wedlund, C., and Plaschke, F.: First detection of Lithium in Mercury's exosphere, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16068, https://doi.org/10.5194/egusphere-egu24-16068, 2024.