The Ice Composition Close to the Surface of Comet 67P/Churyumov-Gerasimenko

Läuter, Matthias; Kramer, Tobias; Rubin, Martin; Altwegg, Kathrin (2022). The Ice Composition Close to the Surface of Comet 67P/Churyumov-Gerasimenko. ACS earth and space chemistry, 6(5), pp. 1189-1203. ACS Publications 10.1021/acsearthspacechem.1c00378

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ABSTRACT: The relation between ice composition in the nucleus of comet 67P/Churyumov-Gerasimenko on the one hand and relative abundances of volatiles in the coma on the other hand is important for the interpretation of density measurements in the environment of the cometary nucleus. For the 2015 apparition, in situ measurements from the two ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) sensors COPS (COmet Pressure Sensor) and DFMS (Double Focusing Mass Spectrometer) determined gas densities at the spacecraft position for the 14 gas species H2O, CO2, CO, H2S, O2, C2H6, CH3OH, H2CO, CH4, NH3, HCN, C2H5OH, OCS, and CS2. We derive the spatial distribution of the gas emissions on the complex shape of the nucleus separately for 50 subintervals of the 2 year mission time. The most active patches of gas emission are identified on the surface. We retrieve the relation between solar irradiation and observed emissions from these patches. The emission rates are compared to a minimal thermophysical model to infer the surface active fraction of H2O and CO2. We obtain characteristic differences in the ice composition close to the surface between the two hemispheres with a reduced abundance of CO2 ice on the northern hemisphere (locations with positive latitude). We do not see significant differences for the ice composition on the two lobes of 67P/C-G.

Item Type:

Journal Article (Original Article)

Division/Institute:

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

UniBE Contributor:

Rubin, Martin, Altwegg, Kathrin

Subjects:

500 Science > 520 Astronomy
600 Technology > 620 Engineering

ISSN:

2472-3452

Publisher:

ACS Publications

Language:

English

Submitter:

Dora Ursula Zimmerer

Date Deposited:

30 Mar 2023 15:13

Last Modified:

30 Mar 2023 15:13

Publisher DOI:

10.1021/acsearthspacechem.1c00378

BORIS DOI:

10.48350/181164

URI:

https://boris.unibe.ch/id/eprint/181164

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