Studying the spectral and geochemical characteristics of Mercury analogs as a foundation for the analysis of BepiColombo data

Kurzfassung

The MErcury Radiometer and Thermal Infrared Spectrometer (MERTIS) of the BepiColombo mission has as main goal to characterize the Hermean surface mineralogy of Mercury by measuring the spectral emissivity of the planet’s surface with a pixel precision of at least 500 mpp. [1] The 2nd of December 2024 there is a possibility for MERTIS to operate and perform surface measurements on an area within the hot pole of Mercury, encompassing the large Beethoven basin. This Region of Interest (ROI) was studied for its geomorphological features and expected mineralogy, by subdividing the area in different terrane types. The main types of terranes within our ROI were identified; (1) Smooth Plains (SP), (2) Intermediate Terrains (IT), (3) Low Reflectance Materials (LRM) and some localized features such as Faculae and Hollows. [2] To prepare for the upcoming remote-sensing measurements of MERTIS, analogue materials to simulate the expected mineralogy within our ROI need be selected and studied in details. Microscopical analysis, as well as reflectance and emissivity spectral analysis of the analogous materials are needed for comparison to the remote sensing data once the BepiColombo spacecraft reaches Mercury and can operate. To simulate the LRM terrane, we selected two types of Aubrites; Bishopville and Norton County, as these materials are highly reduced such as expected for that type of terrane. [3] For this study, microscopical and spectral analysis (in the MIR range) were performed on these samples in the laboratory facility of the German Aerospace Center (DLR) in Berlin. The acquired data are the preliminary steps for the comparison to the future remote sensing data that will be acquired by MERTIS in the near future.