Cyanogen, cyanoacetylene, and acetonitrile in comet 67P and their relation to the cyano radical

Hänni, N.; Altwegg, K.; Balsiger, H.; Combi, M.; Fuselier, S. A.; De Keyser, J.; Pestoni, B.; Rubin, M.; Wampfler, S. F. (2021). Cyanogen, cyanoacetylene, and acetonitrile in comet 67P and their relation to the cyano radical. Astronomy and astrophysics, 647(A22), A22. EDP Sciences 10.1051/0004-6361/202039580

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The cyano radical (CN) is one of the most frequently remotely observed species in space, and is also often observed in comets.
Data for the inner coma of comet 67P/Churyumov-Gerasimenko collected by the high-resolution Double Focusing Mass Spectrometer
(DFMS) on board the Rosetta orbiter revealed an unexpected chemical complexity, and, recently, also more CN than expected from
photodissociation of its most likely parent, hydrogen cyanide (HCN). Here, we derive abundances relative to HCN of three cometary
nitriles (including structural isomers) from DFMS data. Mass spectrometry of complex mixtures does not always allow isolation of
structural isomers, and therefore in our analysis we assume the most stable and abundant (in similar environments) structure, that is
HCN for CHN, CH3CN for C2H3N, HC3N for C3HN, and NCCN for C2N2. For cyanoacetylene (HC3N) and acetonitrile (CH3CN), the
complete mission time-line was evaluated, while cyanogen (NCCN) was often below the detection limit. By carefully selecting periods
where cyanogen was above the detection limit, we were able to follow the abundance ratio between NCCN and HCN from 3.16 au
inbound to 3.42 au outbound. These are the first measurements of NCCN in a comet. We find that neither NCCN nor either of the other
two nitriles is sufficiently abundant to be a relevant alternative parent to CN.

Item Type:

Journal Article (Original Article)


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

UniBE Contributor:

Hänni, Nora Phillys, Altwegg, Kathrin, Balsiger, Hans, Pestoni, Boris Renato, Rubin, Martin, Wampfler, Susanne


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




EDP Sciences




Dora Ursula Zimmerer

Date Deposited:

07 Sep 2021 15:51

Last Modified:

05 Dec 2022 15:52

Publisher DOI:





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