Issue |
A&A
Volume 644, December 2020
|
|
---|---|---|
Article Number | A115 | |
Number of page(s) | 21 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/202039528 | |
Published online | 09 December 2020 |
Irradiation dose affects the composition of organic refractory materials in space
Results from laboratory analogues
1
Université Paris-Saclay, CNRS, Institut d’astrophysique spatiale,
91405
Orsay,
France
e-mail: rurso@ias.u-psud.fr
2
Université Grenoble Alpes, CNRS, IPAG,
38000
Grenoble,
France
3
Aix-Marseille Université, Laboratoire de Physique des Interactions Ioniques et Moléculaires (PIIM) UMR-CNRS 7345,
13397
Marseille,
France
Received:
25
September
2020
Accepted:
5
November
2020
Context. Near- and mid-infrared observations have revealed the presence of organic refractory materials in the Solar System, in cometary nuclei and on the surface of centaurs, Kuiper-belt and trans-neptunian objects. In these astrophysical environments, organic materials can be formed because of the interaction of frozen volatile compounds with cosmic rays and solar particles, and favoured by thermal processing. The analysis of laboratory analogues of such materials gives information on their properties, complementary to observations.
Aims. We present new experiments to contribute to the understanding of the chemical composition of organic refractory materials in space.
Methods. We bombard frozen water, methanol and ammonia mixtures with 40 keV H+ and we warmed the by-products up to 300 K. The experiments enabled the production of organic residues that we analysed by means of infrared spectroscopy and by very high resolution mass spectrometry to study their chemical composition and their high molecular diversity, including the presence of hexamethylenetetramine and its derivatives.
Results. We find that the accumulated irradiation dose plays a role in determining the composition of the residue.
Conclusions. Based on the laboratory doses, we estimate the astrophysical timescales to be short enough to induce an efficient formation of organic refractory materials at the surface of icy bodies in the outer Solar System.
Key words: Kuiper belt: general / astrochemistry / astrobiology / solid state: refractory / methods: laboratory: solid state
© R. G. Urso et al. 2020
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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