Formation de Molécules Organiques Complexes dans l'Espace – FORCOMS

From the chemical point of view, the first phases of the formation of stars like the Sun are characterized by two phenomena: i) the synthesis of several and complex organic molecules (hereinafter called COMs, where the complexity increases with the number of atom in the molecule) found in the so-called hot corinos, and ii) a huge enhancement of the molecular deuteration (namely molecules containing D atoms instead of H atoms), called super-deuteration. Many evidences tell us that the Sun had passed through the hot corino and super-deuteration phase too. For sure, several molecules formed in those ancient eons have survived and have been inherited by bodies of the Solar System: quite certainly comets and meteorites, and, likely, the Earth oceans, as testified by the measured enhanced molecular deuteration. Despite their potential impact on organics delivery on the early Earth and the triggering of life, we know relatively little about the COMs synthesized during the protostellar phase and their fate: what molecules are formed, when, where and how, whether and how they are inherited by the formed planetary system, what role dust plays in this process… are all open questions. With this proposal we aim to focus on two questions: i) what COMs are formed and in what quantity during the protostellar phase, and ii) how reactions on dust grains contribute to the formation of key COMs. For that, we will use a multi-disciplinary approach, based on the complementary expertise of the project Partners. The immediate goals of the project will be: 1) to establish a COMs catalog with their abundances in a hot corino prototype from spectral surveys in the millimeter to Far-IR range, combining astrophysical and spectroscopic expertise. Laboratory measurements coupled with theoretical computations will provide the molecular data necessary to correctly interpret the astrophysical spectra in term of COMs abundances. 2) to understand the role of grains coated by water ices, by studying the synthesis of key COMs, observed in the surveys, both theoretically and experimentally. Theoretical chemistry calculations will explore the catalytic role played by the icy grain surface, and coordinated laboratory experiments will test the D-H atoms exchange between frozen COMs and water ices. An astrochemical model of grain-surface chemistry will simulate the impact on the COMs abundances in the hot corino prototype.