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J. Benkhoff (ESA-ESTEC), J. Helbert (DLR), E.K. Jessberger (University of Muenster), MERTIS Team
Feldspars are expected to belong to Mercury's main constituents. In the NIR-range, however, pure feldspars have no specific spectral signature. The reliable detection of any feldspar and even their detailed classification are highly questionable. In the Thermal Infrared (TIR), however, feldspars can be detected - and specified - by means of their diagnostic spectral signatures: Christiansen frequency, reststrahlen band, and transparency feature. In addition, pyroxenes and most other minerals can be detected and specified in this spectral range. Thermal infrared sectroscopy operating in the range between 7 and 14 µm will provide valuable mineral identification of feldspars and low-iron species that are expected to be prevailing on Mercury's surface. Performing TIR measurements enables identification of spectral features associated with the high radar backscattering efficiency of putative minerals and differentiation between the proposed compositions (water ice, sulfur, cold silicate glasses) for the high-latitude volatiles, something that cannot be done by ground based observing or near-infrared spectroscopy. TIR measurements will allow studying areas of geologic importance where composition can give significant new understanding to relative age of tectonic features. The MERTIS instrument, an imaging spectrometer in the TIR range onboard of ESA's BepiColombo mission to investigate Mercury, will fulfill all the requirements needed to obtain Mercury's surface composition.
The author(s) of this abstract have provided an email address for comments about the abstract: Johannes.Benkhoff@esa.int
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Bulletin of the American Astronomical Society, 37 #3
© 2004. The American Astronomical Soceity.