4-8 October 2015
Hans Harnack Haus
Europe/Berlin timezone
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Contribution Poster

Poster session

Constraining the fractionation process in ices towards IRAS 3283 using NH2D nitrogen isotopologues



Primary authors



The chemical history of the interstellar gas is one major question at the crossroads of many fields of research in astrophysics and astrochemistry, in both the local and the young Universe. The chemical heritage of planetary systems is one particular instance of this problem. Isotopic ratios are usual and powerful tools to follow chemical volatile reservoirs during the evolution of the gas from interstellar clouds to planet forming circumstellar disks. In this respect, the isotopic ratio of nitrogen displays large variations within the Solar System that are not understood, and for which an interstellar origin has recently been proposed and put into question. Part of the problem may amount to an incomplete understanding of the fractionation processes at work in dense clouds. Isotopic exchange has been proposed to take place in ices, with no direct observational, experimental, or theoretical support. In this poster, we present observations of the NH$_2$D and $^{15}$NH$_2$D isotopologues, which allow us to measure directly the nitrogen isotopic ratio in this hydride. The $^{14}$N/$^{15}$N isotopic ratio in these isotopologues is thought to be subject fractionation process in ices inside molecular clouds. By comparing measurements of this isotopic ratio towards the protostar IRAS 3282 and at a small offset from it, we provide observational constraints on the fractionation in ices.