An extended public deuterium fractionation model for the astrochemical community
Résumé
Deuterated species are unique and powerful tools in astronomy since deuterium-to-hydrogen (D/H) enrichment in molecular species provides clues about their original environment of formation, chemistry, and the ionization level of the medium. But the study of the deuterium chemistry is a challenging task because of the limited number of accurately determined rate coefficients and the sheer number of hydrogen-dominated reactions in astrochemical networks. Here, we will present a new extended publicly available deuterium fractionation model available in KIDA database which includes ortho/para chemistry of major protonated species. We will try to highlight the following key questions:(1) How observing few selected deuterated species can be a very effective tool to characterize cold and dark media where most molecules are depleted?(2) Does spin chemistry change the deuterium enrichment of the ISM?(3) Prediction for future observations for deuterated species in dense cores and protoplanetary disks.We will also show and discuss our recent observation to measure the D/H ratio of c-C3H2 in cold envelope of IRAS 16293-2422 as an application. We will also show our prediction to map the D/H ratio of essential molecules in protostellar envelopes and disks using ALMA (and ngVLA in the future).