Thermal annealing of silicates in protoplanetary disks - Laboratory data and modelling

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This project aims at obtaining reliable laboratory data on the physico-chemical processes taking place during thermal annealing of silicate minerals. These data are urgently needed for a consistent astrophysical modelling. The degree of crystallinity is of utmost importance for the opacity, radiative transfer and thermal structure of protoplanetary disks. A variety of minerals - particularly the cosmochemically abundant Mg-rich silicates of the olivine and pyroxene groups - have been observed via infrared spectroscopy of protoplanetary disks and comets. In this project, thermal annealing of these silicates will be traced in the laboratory by infrared spectroscopy of heated amorphous materials. The infrared results will be correlated with those of other methods (e.g. X-ray diffractometry and transmission electron microscopy) to better define the degree of crystallinity as a function of time and annealing temperature. Numerical techniques and ab initio calculations will be used to model the crystallisation process and simulate the evolution of infrared spectra during this process.