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Title: Formaldehyde chemistry in cometary ices: on the prospective detection of NH{sub 2}CH{sub 2}OH, HOCH{sub 2}OH, and POM by the on-board ROSINA instrument of the Rosetta mission

The thermal reactivity of a water-dominated cometary ice analog containing H{sub 2}CO and NH{sub 3} is investigated by means of Fourier transform infrared spectroscopy, mass spectrometry, and B3LYP calculations. Three products are characterized by these techniques: aminomethanol (NH{sub 2}CH{sub 2}OH), methyleneglycol (HOCH{sub 2}OH), and polyoxymethylene (POM, HO-(CH{sub 2}-O) {sub n}-H). Their formation strongly depends on the initial NH{sub 3}/H{sub 2}CO ratio. In addition, the influence of the initial ice composition on the thermal stability of POM has also been investigated. It is shown that POM formed during warming of the ices consists of short-chain polymers (i.e., oligomers of formaldehyde HO-(CH{sub 2}-O) {sub n}-H, n < 5), which are volatile at temperatures higher than 200 K. This suggests that gas-phase detection by the ROSINA instrument on board the Rosetta mission would be the most appropriate method to detect POM. Moreover, the mass spectra presented in this work might help in the interpretation of data that will be recorded by this instrument. Finally, a new scenario to explain the distributed source of formaldehyde observed in comets is discussed.
Authors:
; ; ;  [1] ;  [2]
  1. Aix-Marseille Université, CNRS, PIIM UMR 7345, F-13397 Marseille (France)
  2. Universitat Autònoma de Barcelona (UAB), Departament de Química, E-08193 Bellaterra (Spain)
Publication Date:
OSTI Identifier:
22365342
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 791; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMMONIA; ASTROPHYSICS; COMETS; COSMOLOGY; DETECTION; ELEMENT ABUNDANCE; FORMALDEHYDE; FOURIER TRANSFORM SPECTROMETERS; ICE; MASS SPECTRA; MASS SPECTROSCOPY; SPACE; SPACE VEHICLES; WATER