Project P8: Temperature-dependent photostability and optical properties of realistic cometary ice composites (IFK/Jena)


In the second phase, the studies will focus on the preparation of completely different grains and grain/ice composites taking into account the recent insights on the composition and morphology of cometary dust resulting from the Rosetta rendezvous mission with the comet 67P. In the cometary material, silicates are mixed with an excess of carbonaceous material having an organic, kerogen-like composition. Such a material will be produced by a multistage process in the laboratory. The produced Mg-Fe-silicates will be covered by an ice layer of carbon-bearing molecules that can be converted into a kerogen-like material by VUV irradiation. The final product will be analytically characterized. These silicate/kerogen grains will be covered by water ice or cometary ice blends. The photostability of such ice composites upon VUV photons will be studied at different temperatures relevant for debris disks by the use of IR spectroscopy and mass spectrometry. In addition, the spectral properties of the new cometary ice composites will be measured in the IR and FIR range at different temperatures. We will collaborate with project P5 in order to measure optical constants in the sub-mm range. The results will provide important thermal desorption and photostability data for projects P1−P4.