Origin of molecular oxygen in comet 67P/Churyumov–Gerasimenko

Mousis, O.; Ronnet, T.; Brugger, B.; Ozgurel, O.; Pauzat, F.; Ellinger, Y.; Maggiolo, R.; Wurz, Peter; Vernazza, P.; Lunine, J. I.; Luspay-Kuti, A.; Mandt, K. E.; Altwegg, Kathrin; Bieler, André; Markovits, A.; Rubin, Martin (2016). Origin of molecular oxygen in comet 67P/Churyumov–Gerasimenko. Astrophysical Journal Letters, 823(2), L41. Institute of Physics Publishing IOP 10.3847/2041-8205/823/2/l41

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Molecular oxygen has been detected in the coma of comet 67P/Churyumov-Gerasimenko with abundances in the 1%-10% range by the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis-Double Focusing Mass Spectrometer instrument on board the Rosetta spacecraft. Here we find that the radiolysis of icy grains in low-density environments such as the presolar cloud may induce the production of large amounts of molecular oxygen. We also show that molecular oxygen can be efficiently trapped in clathrates formed in the protosolar nebula (PSN), and that its incorporation as crystalline ice is highly implausible, because this would imply much larger abundances of Ar and N-2 than those observed in the coma. Assuming that radiolysis has been the only O-2 production mechanism at work, we conclude that the formation of comet 67P/Churyumov-Gerasimenko is possible in a dense and early PSN in the framework of two extreme scenarios: (1) agglomeration from pristine amorphous icy grains/particles formed in ISM and (2) agglomeration from clathrates that formed during the disk's cooling. The former scenario is found consistent with the strong correlation between O-2 and H2O observed in comet 67P/Churyumov-Gerasimenko's coma while the latter scenario requires that clathrates formed from ISM icy grains that crystallized when entering the PSN.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences

UniBE Contributor:

Wurz, Peter; Altwegg, Kathrin; Bieler, André and Rubin, Martin

Subjects:

500 Science > 520 Astronomy
500 Science > 530 Physics
600 Technology > 620 Engineering

ISSN:

2041-8205

Publisher:

Institute of Physics Publishing IOP

Language:

English

Submitter:

Katharina Weyeneth-Moser

Date Deposited:

11 Nov 2016 17:38

Last Modified:

25 Apr 2017 13:41

Publisher DOI:

10.3847/2041-8205/823/2/l41

BORIS DOI:

10.7892/boris.89546

URI:

https://boris.unibe.ch/id/eprint/89546

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