Volatiles in the H2O and CO2 ices of comet 67P/Churyumov–Gerasimenko

Rubin, Martin; Altwegg, Kathrin; Berthelier, Jean-Jacques; Combi, Michael R; De Keyser, Johan; Fuselier, Stephen A; Gombosi, Tamas I; Gudipati, Murthy S; Hänni, Nora; Kipfer, Kristina A; Ligterink, Niels F W; Müller, Daniel R; Shou, Yinsi; Wampfler, Susanne F (2023). Volatiles in the H2O and CO2 ices of comet 67P/Churyumov–Gerasimenko. Monthly notices of the Royal Astronomical Society, 526(3), pp. 4209-4233. Oxford University Press 10.1093/mnras/stad3005

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European Space Agency’s Rosetta spacecraft at comet 67P/Churyumov–Gerasimenko (67P) was the first mission that accompanied a comet over a substantial fraction of its orbit. On board was the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis mass spectrometer suite to measure the local densities of the volatile species sublimating from the ices inside the comet’s nucleus. Understanding the nature of these ices was a key goal of Rosetta. We analysed the primary cometary molecules at 67P, namely H2O and CO2, together with a suite of minor species for almost the entire mission. Our investigation reveals that the local abundances of highly volatile species, such as CH4 and CO, are reproduced by a linear combination of both H2O and CO2 densities. These findings bear similarities to laboratory-based temperature-programmed desorption experiments of amorphous ices and imply that highly volatile species are trapped in H2O and CO2 ices. Our results do not show the presence of ices dominated by these highly volatile molecules. Most likely, they were lost due to thermal processing of 67P’s interior prior to its deflection to the inner solar system. Deviations in the proportions co-released with H2O and CO2 can only be observed before the inbound equinox, when the comet was still far from the sun and the abundance of highly volatile molecules associated with CO2 outgassing were lower. The corresponding CO2 is likely seasonal frost, which sublimated and lost its trapped highly volatile species before re-freezing during the previous apparition. CO, on the other hand, was elevated during the same time and requires further investigation.

Item Type:

Journal Article (Original Article)


08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences
08 Faculty of Science > Physics Institute
10 Strategic Research Centers > Center for Space and Habitability (CSH)

UniBE Contributor:

Rubin, Martin, Altwegg, Kathrin, Hänni, Nora Phillys, Kipfer, Kristina Anna, Ligterink, Niels Frank Willem, Müller, Daniel Robert, Wampfler, Susanne


500 Science > 520 Astronomy
500 Science > 530 Physics
600 Technology > 620 Engineering
000 Computer science, knowledge & systems




Oxford University Press




Dora Ursula Zimmerer

Date Deposited:

26 Oct 2023 14:43

Last Modified:

26 Oct 2023 14:43

Publisher DOI:






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