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

TL;DR

This study provides the first infrared spectra and destruction cross sections for 2-aminooxazole, assessing its stability in astrophysical environments and implications for prebiotic chemistry in space.

Contribution

It offers new IR spectra, UV absorption data, and destruction cross sections for 2-aminooxazole, advancing understanding of its astrochemical stability and potential role in prebiotic synthesis.

Findings

2-aminooxazole has specific IR spectra at various temperatures.

Destruction cross sections under UV and electron irradiation were quantified.

2-aminooxazole can survive in dense cloud ice mantles but is unstable on cold Solar System surfaces.

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.