Searches for the prebiotically-relevant cyanamide (NH2CN) 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 13C isotopologues of NH2CN 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 (∼ 1.7%) is similar to that of formamide (NH2CHO), which may suggest that these two molecules share NH2 as a common precursor. The NH2CN/NH2CHO 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 NH2CN on grains through the NH2 + CN reaction using the chemical model MAGICKAL. Grain-surface chemistry appears capable of reproducing the gas-phase abundance of NH2CN with the correct choice of physical parameters.
@article{arxiv.1712.09548,
title = {First detection of cyanamide (NH$_2$CN) towards solar-type protostars},
author = {A. Coutens and E. R. Willis and R. T. Garrod and H. S. P. Müller and T. L. Bourke and H. Calcutt and M. N. Drozdovskaya and J. K. Jørgensen and N. F. W. Ligterink and M. V. Persson and G. Stéphan and M. H. D. van der Wiel and E. F. van Dishoeck and S. F. Wampfler},
journal= {arXiv preprint arXiv:1712.09548},
year = {2018}
}