First detection of cyanamide (NH₂CN) towards solar-type protostars

2017/12/27 by A. Coutens, E. R. Willis, R. T. Garrod +11 · 2 citations
Physics and Astronomy · #astro-ph.SR #astro-ph.GA

paper · pdf · doi:10.1051/0004-6361/201732346

published as A&A 612, A107 (2018) · Accepted in A&A

arxiv created 2017/12/27 · arxiv updated 2018/05/09

Abstract

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.

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• Digging into the Massive Protostar S255IR NIRS3: A Study of Nitrogen-bearing Molecules and Their Prebiotic Chemistry
• The Reaction between Atomic Carbon and Molecular Nitrogen as a Source of Cyanamide and Carbodiimide on Interstellar Ices