Spectral Curvature in the Visible as an Indicator of Mercury's Space-Weathering

Kurzfassung

Spectroscopy is a key tool for in�vestigating surface composition and space-weathering of planetary bodies. Because of its proximity to the Sun, Mercury’s surface is exposed to extreme conditions and environment (e.g. extreme temperature variation, high rate of impact). Among the youngest features at the surface of Mercury are the hollows [e.g. 1]. Multispectral observations by the Mercury Dual Imaging System (MDIS) wide angle camera (WAC) onboard MESSENGER revealed that hollows exhibit a reflectance twice higher than the average surface of Mercury and a weak absorption feature centered around 630 nm [e.g. 1, 2]. Spectral reflectance measured by the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) lack absorption features even for the hollows materials observed with MDIS [3]. However, MASCS spectra exhibit a strong concave curvature between 300 and 600 nm, unique to hollows [3]. Here, we present an analysis of the MASCS spectral curvature on the entire surface of Mercury in order to investigate the relationship between curvature, composition and space-weathering.