{
  "id": "1711.05184",
  "version": "v1",
  "published": "2017-11-14T16:44:32.000Z",
  "updated": "2017-11-14T16:44:32.000Z",
  "title": "Chemical modelling of complex organic molecules with peptide-like bonds in star-forming regions",
  "authors": [
    "David Quénard",
    "Izaskun Jiménez-Serra",
    "Serena Viti",
    "Jon Holdship",
    "Audrey Coutens"
  ],
  "comment": "18 pages, 5 figures, accepted for publication in MNRAS",
  "categories": [
    "astro-ph.SR",
    "astro-ph.GA"
  ],
  "abstract": "Peptide bonds (N-C=O) play a key role in metabolic processes since they link amino acids into peptide chains or proteins. Recently, several molecules containing peptide-like bonds have been detected across multiple environments in the interstellar medium (ISM), growing the need to fully understand their chemistry and their role in forming larger pre-biotic molecules. We present a comprehensive study of the chemistry of three molecules containing peptide-like bonds: HNCO, NH$_2$CHO, and CH$_3$NCO. We also included other CHNO isomers (HCNO, HOCN), and C$_2$H$_3$NO isomers (CH$_3$OCN, CH$_3$CNO) to the study. We have used the \\uclchem gas-grain chemical code and included in our chemical network all possible formation/destruction pathways of these peptide-like molecules recently investigated either by theoretical calculations or in laboratory experiments. Our predictions are compared to observations obtained toward the proto-star IRAS16293$-$2422 and the L1544 pre-stellar core. Our results show that some key reactions involving the CHNO and C$_2$H$_3$NO isomers need to be modified to match the observations. Consistently with recent laboratory findings, hydrogenation is unlikely to produce NH$_2$CHO on grain surfaces, while a combination of radical-radical surface reactions and gas-phase reactions is a better alternative. In addition, better results are obtained for NH$_2$CHO when a slightly higher activation energy of 25$\\,$K is considered for the gas-phase reaction $\\rm NH_2 + H_2CO \\rightarrow NH_2CHO + H$. Finally, our modelling shows that the observed correlation between NH$_2$CHO and HNCO in star-forming regions may come from the fact that HNCO and NH$_2$CHO react to temperature in the same manner rather than from a direct chemical link between the two species.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2017-11-14T16:44:32.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "complex organic molecules",
      "star-forming regions",
      "molecules containing peptide-like bonds",
      "chemical modelling",
      "gas-phase reaction"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 18,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}