Planetesimal Formation at High Temperatures

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Early phases of planet formation strongly depend of the material properties of the particles present as dust. Especially radial inward drift and high temperatures have a strong influence on the aggregation in the warm, inner parts of protoplanetary disks. First laboratory experiments show that during early phases of planetesimal formation high temperatures indeed can alter the sticking capabilities of dust grains tremendously. This project will study this in a systematic way as the evolution of chondritic as well as model mineral samples from cooler to higher temperatures will be simulated. Protoplanetary analog samples will be produced, heated and their composition will be analyzed by X-ray diffraction, Mössbauer spectroscopy, optical imaging, electronmicroscopical methods and particle size analysis. These samples will be studied cool and warm for static and dynamical sticking properties in tensile strength and collision experiments. Ultimate goal is to develop an idea on the efficiency of local planetesimal formation. Especially, in view of the large number and variation of extrasolar planets within the warm inner parts close to their host stars this is an approach for understanding planet formation that found little consideration so far.