The formation of peptide-like molecules on interstellar dust grains

N. F.W. Ligterink, J. Terwisscha van Scheltinga, V. Taquet, J. K. Jørgensen, S. Cazaux, E. F. van Dishoeck, H. Linnartz

Research output: Contribution to journalArticleScientificpeer-review

28 Citations (Scopus)

Abstract

Molecules with an amide functional group resemble peptide bonds, the molecular bridges that connect amino acids, and may thus be relevant in processes that lead to the formation of life. In this study, the solid state formation of some of the smallest amides is investigated in the laboratory. To this end, CH4:HNCO ice mixtures at 20 K are irradiated with far-UV photons, where the radiation is used as a tool to produce the radicals required for the formation of the amides. Products are identified and investigated with infrared spectroscopy and temperature-programmed desorption mass spectrometry. The laboratory data show that NH2CHO, CH3NCO, NH2C(O)NH2, CH3 C(O)NH2, and CH3NH2 can simultaneously be formed. The NH2CO radical is found to be key in the formation of larger amides. In parallel, ALMA observations towards the low-mass protostar IRAS 16293-2422B are analysed in search of CH3NHCHO (N-methylformamide) and CH3C(O)NH2 (acetamide). CH3C(O)NH2 is tentatively detected towards IRAS 16293-2422B at an abundance comparable with those found towards high-mass sources. The combined laboratory and observational data indicate that NH2CHO and CH3C(O)NH2 are chemically linked and form in the ice mantles of interstellar dust grains. A solid-state reaction network for the formation of these amides is proposed.

Original languageEnglish
Pages (from-to)3628-3643
Number of pages16
JournalMonthly Notices of the Royal Astronomical Society
Volume480
Issue number3
DOIs
Publication statusPublished - 1 Jan 2018

Keywords

  • Astrochemistry
  • Individual objects: IRAS 16293-2422
  • Methods: laboratory: molecular
  • Molecular processes
  • Techniques: spectroscopic

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