ORIGIN OF MOLECULAR OXYGEN IN COMET 67P/CHURYUMOV–GERASIMENKO

Journal Article · Wed Jun 01 00:00:00 EDT 2016 · Astrophysical Journal Letters

DOI:https://doi.org/10.3847/2041-8205/823/2/L41· OSTI ID:22654313

Mousis, O.; Ronnet, T.; Brugger, B.; Vernazza, P. ^[1]; Ozgurel, O.; Pauzat, F.; Ellinger, Y.; Markovits, A. ^[2]; Maggiolo, R. ^[3]; Wurz, P.; Altwegg, K.; Bieler, A.; Rubin, M. ^[4]; Lunine, J. I. ^[5]; Luspay-Kuti, A.

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1. Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, F-13388, Marseille (France)
2. Laboratoire de Chimie Théorique, Sorbonne Universités, UPMC Univ. Paris 06, CNRS UMR 7616, F-75252 Paris CEDEX 05 (France)
3. Royal Institute for Space Aeronomy, 3 Avenue Circulaire, Brussels (Belgium)
4. Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern (Switzerland)
5. Department of Astronomy and Carl Sagan Institute, Space Sciences Building Cornell University, Ithaca, NY 14853 (United States)

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{sub 2} than those observed in the coma. Assuming that radiolysis has been the only O{sub 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{sub 2} and H{sub 2}O 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.

• OSTI ID: 22654313
• Journal Information: Astrophysical Journal Letters, Vol. 823, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABUNDANCE
AGGLOMERATION
CLATHRATES
COMETS
CORRELATIONS
DENSITY
IONS
MASS
MASS SPECTROMETERS
MOLECULES
ORBITS
ORIGIN
OXYGEN
RADIOLYSIS
SOLAR NEBULA
SOLIDS
SPACE VEHICLES
TRAPPING
WATER