Spectral measurements on analogues at PEL

Abstract

At the Planetary Emissivity Laboratory (PEL) of the German Aerospace Center, DLR, in Berlin we are building a database of spectral measurements on meteorites and mineralogical analogues to asteroid surfaces. Bi-directional reflectance of samples in the 1 to 100 µm spectral range, are measured by using an evacuated (10-4 bar) Bruker Vertex 80V FTIR spectrometer and a Bruker A513 reflection unit, allowing phase angles between 26° and 170°. Emissivity in the 1 to 100 µm spectral range is measured with the same instrument coupled with an external emissivity chamber, for sample temperatures from low (50° C) to very high (above 500° C). We present new measurements on phyllosilicates, sulfates and carbonates, in various grain size ranges and for fresh samples (measured at surface temperature around 70 ° C) and on the same samples after being heated to 500 K, to simulate the thermal history that surface minerals on the asteroid 2008 EV5, scientific target of the ESA Marco Polo-R mission, underwent during its revolution around the Sun.