1,1,4,1,3,1,1,- 1University of Bern, Physics Institute, Space Research & Planetary Sciences, Bern, Switzerland (martin.rubin@unibe.ch)
- 2LATMOS/IPSL-CNRS-UPMC-UVSQ, 4 Avenue de Neptune, F-94100, Saint-Maur, France
- 3Department of Climate, Space Sciences, and Engineering, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109, USA
- 4Belgian Institute for Space Aeronomy, BIRA-IASB, Ringlaan 3, B-1180 Brussels, Belgium
- 5Space Science Directorate, Southwest Research Institute, 6220 Culebra Rd., San Antonio, TX 78228, USA
- 6Department of Physics and Astronomy, The University of Texas at San Antonio, San Antonio, TX 78249, USA
- 7Center for Space and Habitability, University of Bern, Gesellschaftsstrasse 6, CH-3012 Bern, Switzerland
Between 2014 and 2016, ESA’s Rosetta mission followed comet 67P/Churyumov-Gerasimenko (67P). During that time, the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA, Balsiger et al. 2007) mass spectrometer suite monitored the composition of the gas coma and its evolution along the part of the comet’s trajectory from more than 3.5 au inbound, through perihelion at 1.24 au, and outbound again to almost 4 au.
The cyano radical, CN, is a molecule that is regularly observed in the coma of comets. Its origin, however, has been debated in the literature (Fray et al. 2005, Hänni et al. 2020). CN may have been released directly in the impactor plume formed by NASA’s Deep Impact mission at comet Tempel 1 (Cochran et al. 2007, Jackson et al. 2009). On the other hand, CN is also produced from the dissociation of higher-mass CN-bearing molecules, such as C2N2, HCN, HC3N, and CH3CN (Hänni et al. 2021), but these species are not always abundant enough to explain the amount of CN observed in the coma (Bockelée-Morvan et al. 1984) or the corresponding dissociation times or scale lengths may not match (Bockelée-Morvan and Crovisier 1985, Haser 1957, Huebner and Mukherjee 2015).
In this presentation, we will report on ROSINA data of CN for almost the entire Rosetta mission. Specifically, we will investigate the possibility that at least a part of the CN is stored as a parent radical species inside the ices of comet 67P’s nucleus.
References
- Balsiger et al., ROSINA – Rosetta Orbiter Spectrometer for Ion and Neutral Analysis, SSR, 128(1), 745–801, 2007.
- Bockelée-Morvan et al., Hydrogen cyanide in comets - Excitation conditions and radio observations of comet IRAS-Araki-Alcock 1983d, A&A 141, 2, 411-418, 1984.
- Bockelée-Morvan and Crovisier, Possible parents for the cometary CN radical - Photochemistry and excitation conditions, A&A 151, 90, 1985.
- Cochran et al., Observations of Comet 9P/Tempel 1 with the Keck 1 HIRES instrument during Deep Impact, Icarus, 187, 156-166, 2007
- Fray et al., The origin of the CN radical in comets: A review from observations and models, PSS, 53, 12, 1243-1262, 2005.
- Hänni et al., First in situ detection of the CN radical in comets and evidence for a distributed source, MNRAS 498, 2239–2248, 2020
- Hänni et al., Cyanogen, cyanoacetylene, and acetonitrile in comet 67P and their relation to the cyano radical, A&A 647, A22, 2021.
- Haser, Distribution d’intensité dans la tête d’une comète, Bulletins de l'Académie Royale de Belgique, 43, 740–750, 1957.
- Huebner and Mukherjee, Photoionization and photodissociation rates in solar and blackbody radiation fields, PSS 106, 11–45, 2015.
- Jackson et al., The temporal changes in the emission spectrum of comet 9P/Tempel 1 after deep impact, ApJ, 698, 1609-1619, 2009
How to cite: Rubin, M., Altwegg, K., Berthelier, J.-J., Bonny, R. F., Combi, M. R., De Keyser, J., Doriot, A. C., Stephen A., S. A., Gombosi, T. I., Hänni, N. P., Müller, D. R., and Wampfler, S. F.: CN storage in comet 67P/Churyumov-Gerasimenko, EPSC-DPS Joint Meeting 2025, Helsinki, Finland, 7–12 Sep 2025, EPSC-DPS2025-258, https://doi.org/10.5194/epsc-dps2025-258, 2025.
