MERTIS@Mercury: First Attempt in Mapping the Hermean Surface Mineralogy

Kurzfassung

The MERTIS (MErcury Radiometer and Thermal Infrared Spectrometer) is a mid-infrared imaging instrument, onboard the BepiColombo ESA/JAXA mission to Mercury, launched in October 2018. After arrival in 2026, among other objectives, it will map the mineralogy of the surface of Mercury [1,2]. Part of MERTIS is the Thermal Infrared spectrometer (TIS) covering the wavelength range from 7 to 14 μm. The MERTIS instrument is one of the few detectors used during the 5th flyby at Mercury, resulting in the first thermal infrared data of the hermean surface from a spacecraft after radiometer studies by Mariner 10 [3]. While the footprint is still large (26-30 km) due to the distance of nearly 40000 km during the flyby, the first results already allow distinguishing surface details. One challenge is to derive quantitative mineralogical information from the vast amount of spectra. One way is to model modal mineral data using complex unmixing routines, which provide detailed mineralogy, but require much time and input [e.g., 4]. A simple and fast method to obtain maps of the mineral distribution is the use of simple band ratios instead.