Enceladus and Europa are among the most interesting places in the Solar System. In the vicinity of giant planets, these moons are exposed to energetic ions and electrons, as well as UV radiation from the Sun. The surface temperatures of those two moons range from 60 to 120 K, and their composition is dominated by water ice together with other minor compounds. For the Jovian moon Europa, other icy components include CO2, SO2, N2, and possibly NH3. Recent flybys of Saturn's mon Enceladus by the NASA Cassini space probe have performed measurements of its surface composition, and indicated that besides water ice, other components are CO2, NH3, CH4, and possibly methanol.The molecules on the surface of these moons are continuously modified by space weathering mainly due to the incoming ionizing radiation such as VUV photons, as well as energetic electrons and ions originating from the solar wind, planetary magnetospheres, and cosmic rays. This induces chemical changes and leads to the formation of complex organic molecules, some of them of astrobiological importance, such as amino acids and nucleobases. The objective of this research project is to simulate the physico-chemical changes induced by ionizing radiation at the surface of Enceladus and Europa, to probe and quantify the formation of complex molecules on these moons. The experiments will be performed inside ultra-high vacuum chamber coupled to the GANIL ion accelerator at Caen, France, under supervision of Dr. Philippe Boduch. It will be employed swift ions up to 200 Mev/u (e.g. Ni, O, Fe) to simulate the effect of cosmic ray over these cold outer Solar System moons. We will determine destruction cross section and the formation cross section of daughter species induced by radiolysis in the samples. This laboratory is equipped with a state-of-the-art experimental facility to carry out infrared spectroscopic in-situ analysis of astrochemical simulated samples. After the irradiation protocol the sample will be conduced, in a clean and evacuated vessel and at a room temperature, to be analyzed by chromatography techniques at the Chemical department of the Université Nice Sophia Antipolis, Nice, France (in collaboration with Dr. Uwe Meierhenrich).The current project is a natural extension of the researches performed by the proponent in the astrochemistry field. It is expected that the new analytical technique that will be employed in this research (chromatography) will help to clarifies crucial physico-chemical processes leading to the formation of prebiotic molecules on icy moons, and help addressing some unanswered questions related to the origin of life in the Solar System.
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