Properties of Interstellar Dust Grains

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The main goal of the project is to identify grains of interstellar origin in the data set collected by the Cassini dust detector, which is capable to measure the dynamic properties and the composition of the impacting particles. The analysis of their mass spectra provides for the first time unequivocal information about the composition of solid material at the earliest phases of planet formation as well as about the production rates of galactic dust in carbon-rich stars, red giants, and supernovae. The current knowledge of the composition of interstellar dust (ISD) stemming dominantly from astronomical observations is extremely limited. The Stardust spaceprobe may have collected a few interstellar grains, but so far the examination team has not yet identified such grains within the aerogel samples. The dust instrument onboard the Cassini spaceprobe provides an unique opportunity to obtain in-situ ISD data because shortly after Cassini’s entry into its orbit around Saturn, the ISD observation conditions became favourable. Furthermore, ISD particles can be reliably identified in the Cassini data set because their kinematic and compositional properties are distinct from grains forming Saturn’s rings as well as from interplanetary grains.