First detection of cyanamide (NH$_2$CN) towards solar-type protostars

Abstract : Searches for the prebiotically-relevant cyanamide (NH$_2$CN) towards solar-type protostars have not been reported in the literature. We here present the first detection of this species in the warm gas surrounding two solar-type protostars, using data from the Atacama Large Millimeter/Submillimeter Array Protostellar Interferometric Line Survey (PILS) of IRAS 16293-2422 B and observations from the IRAM Plateau de Bure Interferometer of NGC1333 IRAS2A. We furthermore detect the deuterated and $^{13}$C isotopologues of NH$_2$CN towards IRAS 16293-2422 B. This is the first detection of NHDCN in the interstellar medium. Based on a local thermodynamic equilibrium analysis, we find that the deuteration of cyanamide ($\sim$ 1.7%) is similar to that of formamide (NH$_2$CHO), which may suggest that these two molecules share NH$_2$ as a common precursor. The NH$_2$CN/NH$_2$CHO abundance ratio is about 0.2 for IRAS 16293-2422 B and 0.02 for IRAS2A, which is comparable to the range of values found for Sgr B2. We explored the possible formation of NH$_2$CN on grains through the NH$_2$ + CN reaction using the chemical model MAGICKAL. Grain-surface chemistry appears capable of reproducing the gas-phase abundance of NH$_2$CN with the correct choice of physical parameters.
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Astronomy and Astrophysics - A&A, EDP Sciences, 2018, 612, pp. id.A107. 〈10.1051/0004-6361/201732346〉
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Contributeur : Marie-Paule Pomies <>
Soumis le : mardi 16 janvier 2018 - 08:37:34
Dernière modification le : mardi 29 mai 2018 - 12:51:09

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Audrey Coutens, E. R. Willis, R. T. Garrod, H. S. P. Müller, T. L. Bourke, et al.. First detection of cyanamide (NH$_2$CN) towards solar-type protostars. Astronomy and Astrophysics - A&A, EDP Sciences, 2018, 612, pp. id.A107. 〈10.1051/0004-6361/201732346〉. 〈hal-01685042〉



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