Methylammonium methylcarbamate thermal formation in interstellar ice analogs: a glycine salt precursor in protostellar environments
| Autor: | Patrice Theulé, Fabien Borget, Thierry Chiavassa, Fabrice Duvernay, J.-B. Bossa, Louis Le Sergeant d'Hendecourt |
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| Přispěvatelé: | Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Sud - Paris 11 (UP11) |
| Rok vydání: | 2009 |
| Předmět: |
Physics
Astrochemistry Methylamine Interstellar ice Photodissociation Infrared spectroscopy Astronomy and Astrophysics Context (language use) Astrophysics 010402 general chemistry Photochemistry 01 natural sciences 0104 chemical sciences Astrobiology [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry Reaction rate chemistry.chemical_compound chemistry 13. Climate action Space and Planetary Science 0103 physical sciences Glycine 010303 astronomy & astrophysics |
| Zdroj: | Astronomy and Astrophysics-A&A Astronomy and Astrophysics-A&A, 2009, 506 (2), pp.601-608. ⟨10.1051/0004-6361/200912850⟩ Astronomy and Astrophysics-A&A, EDP Sciences, 2009, 506 (2), pp.601-608. ⟨10.1051/0004-6361/200912850⟩ |
| ISSN: | 1432-0746 0004-6361 |
| DOI: | 10.1051/0004-6361/200912850 |
| Popis: | International audience; Context. Analyses of dust cometary grains collected by the Stardust spacecraft have shown the presence of amines and amino acids molecules, and among them glycine (NH 2 CH 2 COOH). We show how the glycine molecule could be produced in the protostellar environments before its introduction into comets. Aims. We study the evolution of the interstellar ice analogues affected by both thermal heating and vacuum ultraviolet (VUV) photons, in addition to the nature of the formed molecules and the confrontation of our experimental results with astronomical observations. Methods. Infrared spectroscopy and mass spectrometry are used to monitor the evolution of the H 2 O:CO 2 :CH 3 NH 2 and CO 2 :CH 3 NH 2 ice mixtures during both warming processes and VUV photolysis. Results. We first show how carbon dioxide (CO 2) and methylamine (CH 3 NH 2) thermally react in water-dominated ice to form methylammonium methylcarbamate [CH 3 NH + 3 ][CH 3 NHCOO − ] noted C. We then determine the reaction rate and activation energy. We show that C thermal formation can occurs in the 50-70 K temperature range of a protostellar environment. Secondly, we report that a VUV photolysis of a pure C sample produces a glycine salt, methylammonium glycinate [CH 3 NH + 3 ][NH 2 CH 2 COO − ] noted G. We propose a scenario explaining how C and subsequently G can be synthesized in interstellar ices and precometary grains. Conclusions. [CH 3 NH + 3 ][CH 3 NHCOO − ] could be readily formed and would act as a glycine salt precursor in protostellar environments dominated by thermal and UV processing. We propose a new pathway leading to a glycine salt, which is consistent with the detection of glycine and methylamine within the returned samples of comet 81P/Wild 2 from the Stardust mission. |
| Databáze: | OpenAIRE |
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