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Institut des Sciences Moléculaires d'Orsay


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Accueil > Séminaires > Année 2024 > Séminaire de Romain Basalgète (19 mars)

Séminaire de Romain Basalgète (19 mars)

Laboratory Astrophysics Group of the Max Planck Institute for Astronomy

par Martrenchard-Barra Séverine - 12 mars


Le séminaire aura lieu en VISIOCONFERENCE :
demander le lien à seminaires.ismo@universite-paris-saclay.fr

Physical and chemical processes in molecular ices in the interstellar medium

Molecular ices play a central role in the evolution of the interstellar medium, which is commonly described as the space between stars. These ices form on the surface of sub-micrometric refractory solids that populates the cold regions (T < 150 K) and they are mainly composed of H2O, followed by species such as CO, CO2, NH3, CH4 and CH3OH. The interaction of energetic particles (photons, electrons) with these ices induces several physical and chemical processes that influence the molecular composition of the interstellar medium and, ultimately, that of planetesimals and comets. For instance, photo-desorption, which describes the desorption of molecules from the ice surface due to its photo-irradiation, plays a role in the gas-to-ice exchanges and it is believed to be responsible for the observation of several species in the gas phase of the cold regions, where thermal energy is not sufficient to evaporate the ices. The irradiation of ices also induces chemistry. Indeed, during the last decades, a wide range of experimental studies have shown that it is possible to produce complex species, including pre-biotic molecules and their precursors, by irradiation of ice analogues made of the simple molecules cited above. However, the current state of the experimental techniques used in those astrochemistry studies limits our understanding of the chemical pathways in irradiated ices and prevents a clear identification of the complex molecules formed.
In this talk, I will sum up my research achievements regarding the study of these processes and I will propose some experimental ideas to go further on our understanding of ice chemistry.