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UV-photoprocessing of interstellar ice analogs: Detection of hexamethylenetetramine-based
species
Muñoz Caro G.M., Meierhenrich U.J., Schutte W.A., Thiemann W.H.-P. and Greenberg J.M.
Abstract The physical conditions governing the dense cloud environment are reproduced in a high vacuum experimental setup at low temperature T = 12 K. The accretion and photoprocessing of ices on grain surfaces is simulated by depositing an ice layer on a cold finger, while it is irradiated by ultraviolet (UV) photons. After irradiation the sample is slowly warmed to room temperature; a residue remains, containing the most refractory products of photo- and thermal process-ing. In this paper we report on the analysis of the residues performed by means of gas chromatography-mass spectrometry (GC–MS). A number of new molecules based on hexamethylenetetramine (HMT, C6H12N4), the most abundant component of the residues reported here, were detected: methyl-HMT (C6H11N4–CH3), hydroxy-HMT (C6H11N4–OH), methanyl-HMT (C6H11N4–CH2OH), amin-aldehyd-HMT (C6H11N4–NH–CHO) and methanyl-aldehyd-HMT (C6H11N4–CHOH–CHO). To the best of our knowledge, this is the first reported synthesis of these molecules. Currently, these are the heaviest identified com-ponents of the residue. These species might also be present in the interstellar medium, given that the ice was submitted to high temperatures, of the order of 300 K, and form part of comets. Our work serves as preparation for the ESA-Rosetta mission, which plans to do in situ analysis of the composition of a comet nucleus with the COSAC instrumentation.
Astronomy & Astrophysics 413 (2004), 209-216.
This article was cited in:
Meierhenrich UJ, Thiemann WHP: Photochemical concepts on the origin
of biomolecular
asymmetry. Orig. Life
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Munoz Caro GM, Meierhenrich UJ, Schutte WA, Barbier B, Arcones
Segovia A, Rosenbauer H,
Thiemann WHP, Brack A, Greenberg JM: Amino
acids from ultraviolet irradiation of interstellar ice
analogues.
Nature 416 (2002), 403-406
Meierhenrich UJ, Thiemann WHP, Goesmann F, et al.: Enantioselective
amino acid analysis in
cometary matter planned for the Cosac instrument
onboard Rosetta lander. In: Lacoste H (ed.)
Exo-Astrobiologie. ESA SP-518, ISBN: 92-9092-828-X,
the Netherlands (2002), p. 477-478.
Meierhenrich U.J., Thiemann W.H.-P. Muñoz Caro G.M., Schutte
W.A., Greenberg J.M.:
Simulated Cometary Matter as a Test
for Enantiomer Separating Chromatography for Use on
Comet 46P/Wirtanen.
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investigation of cometary
matter onboard Rosetta Lander.
Enantiomer 6 (2001), 97-99.
Last updated January 2004