Laboratory experiments to unveil the molecular reactivity occurring during the processing of ices in the protosolar nebula

International audienceUsing laboratory experiments, we investigate the role of photo and thermal degradation in the possible complexification mechanisms of organic matter that may originate from interstellar ices prior to, or during the formation of the Solar System. We perform High Resolution Orbitrap Mass Spectrometry on organic residues formed from the photo- and thermochemical alterations of Interstellar Medium (ISM) dirty ice laboratory analogues. We probe, at the molecular level, the possible effects within the protosolar nebula on the composition and structure of these organic refractory materials obtained from an initial ice composition representative of astrophysical ices. We show that nitrogen incorporation, by competing with the carbon, has a strong influence on the final composition of the residue. NH3 rich ices lead to a group of unsaturated molecules in the final residue, while H2O rich ices lead to saturated ones. Finally, we observe and discuss the strong effect of UV irradiation on the decarboxylation on organic matter and discuss potential implications of this result for the protosolar nebula