Ion chemistry in the coma of comet 67P near perihelion

Fuselier, S. A.; Altwegg, Kathrin; Balsiger, Hans; Berthelier, J. J.; Beth, A.; Bieler, André; Briois, C.; Broiles, T. W.; Burch, J. L.; Calmonte, Ursina Maria; Cessateur, G.; Combi, M.; De Keyser, J.; Fiethe, B.; Galand, M.; Gasc, Sébastien; Gombosi, T. I.; Gunell, H.; Hansen, K. C.; Hässig, Myrtha; ... (2016). Ion chemistry in the coma of comet 67P near perihelion. Monthly notices of the Royal Astronomical Society, 462(Suppl 1), S67-S77. Oxford University Press 10.1093/mnras/stw2149

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The coma and the comet–solar wind interaction of comet 67P/Churyumov–Gerasimenko changed dramatically from the initial Rosetta spacecraft encounter in 2014 August through perihelion in 2015 August. Just before equinox (at 1.6 au from the Sun), the solar wind Signal disappeared and two regions of different cometary ion characteristics were observed. These ‘outer’ and ‘inner’ regions have cometary ion characteristics similar to outside and inside the ion pileup region observed during the Giotto approach to comet 1P/Halley. Rosetta/DoubleFocusing Mass Spectrometer ion mass spectrometer observations are used here to investigate the H₃O+/H₂O+ ratio in the outer and inner regions at 67P/ Churyumov–Gerasimenko. The H₃O+/H₂O+ ratio and the H₃O+ signal are observed to increase in the transition from the outer to the inner region and the H₃O+ signal appears to be weakly correlated with cometary ion energy. These ion composition changes are similar to the ones observed during the 1P/Halley flyby. Modelling is used to determine the importance of neutral composition and transport of neutrals and ions away from the nucleus. This modelling demonstrates that changes in the H₃O+/H₂O+ ratio appear to be driven largely by transport properties and only weakly by neutral composition in the coma.

Item Type:

Journal Article (Original Article)

Division/Institute:

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

UniBE Contributor:

Altwegg, Kathrin; Balsiger, Hans; Bieler, André; Calmonte, Ursina Maria; Gasc, Sébastien; Hässig, Myrtha; Le Roy, Léna; Rubin, Martin; Sémon, Thierry and Wurz, Peter

Subjects:

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

ISSN:

0035-8711

Publisher:

Oxford University Press

Language:

English

Submitter:

Katharina Weyeneth-Moser

Date Deposited:

06 Jul 2017 10:50

Last Modified:

06 Jul 2017 10:50

Publisher DOI:

10.1093/mnras/stw2149

BORIS DOI:

10.7892/boris.97009

URI:

https://boris.unibe.ch/id/eprint/97009

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