2-aminooxazole in astrophysical environments: IR spectra and destruction cross sections for energetic processing

Abstract

2-aminooxazole (2AO), a N-heterocyclic molecule, has been proposed as an intermediate in prebiotic syntheses. It has been demonstrated that it can be synthesized from small molecules such as cyanamide and glycoaldehyde, which are present in interstellar space. The aim of this work is to provide infrared spectra, in the solid phase for conditions typical of astrophysical environments and to estimate its stability toward UV photons and cosmic rays. Infrared (4000-600 cm${}^{-1}$) absorption spectra at 20 K, 180 K, and 300 K, IR band strengths, and room temperature UV (120-250 nm) absorption spectra are given for the first time for this species. Destruction cross-sections of 9.5 10${}^{-18}$ cm${}^2$ and 2 10${}^{-16}$ cm${}^2$ were found in the irradiation at 20 K of pure 2AO and 2AO:H${}_2$O ices with UV (6.3-10.9 eV) photons or 5 keV electrons, respectively. These data were used for the estimate of half-life times for the molecule in different environments. It is estimated that 2AO could survive UV radiation and cosmic rays in the ice mantles of dense clouds beyond cloud collapse. In contrast, it would be very unstable at the surface of cold Solar System bodies like Kuiper belt objects, but the molecule could still survive within dust grain agglomerates or cometesimals.

31 pages, 9 figures. Accepted to be published in The Astrophysical Journal

References in corpus (10)

• Photochemistry and astrochemistry: photochemical pathways to interstellar complex organic molecules
• The ALMA Protostellar Interferometric Line Survey (PILS): First results from an unbiased submillimeter wavelength line survey of the Class 0 protostellar binary IRAS 16293-2422 with ALMA
• The Spatial Distribution of Complex Organic Molecules in the L1544 Pre-stellar Core
• The largest oxigen bearing organic molecule repository
• Formation of Complex Organic Molecules in Cold Interstellar Environments through non-diffusive grain-surface and ice-mantle chemistry
• Vacuum-UV spectroscopy of interstellar ice analogs. I. Absorption cross-sections of polar-ice molecules
• In-situ measurements of the radiation stability of amino acids at 15-140 K
• An IR study of pure and ion irradiated frozen formamide
• Vacuum-UV spectroscopy of interstellar ice analogs. II. Absorption cross-sections of nonpolar ice molecules
• Photoprocessing of formamide ice: route towards prebiotic chemistry in space

Cited by in corpus (4)

• Infrared spectra of solid indene pure and in water ice. Implications for observed IR absorptions in TMC-1
• Laboratory experiments on the sublimation of methane through ice dust layers and applications to cometary activity
• Hydroxylamine in Astrophysical Ices: IR Spectra and Cosmic Ray-Induced Radiolytic Chemistry
• Chemistry of Dark Molecular Clouds