A comparison between the two lobes of comet 67P/Churyumov-Gerasimenko based on D/H ratios in H₂O measured with the Rosetta/ROSINA DFMS

Isaac R. H. G. Schroeder I (1) , Kathrin Altwegg (1) , Hans Balsiger (1) , Jean-Jacques Berthelier (2) , Michael R. Combi (3) , Johan de Keyser (4) , Björn Fiethe (5) , Stephen A. Fuselier (6, 7) , Tamas I. Gombosi (3) , Kenneth C. Hansen (3) , Martin Rubin (1) , Yinsi Shou (3) , Valeriy M. Tenishev (3) , Thierry Sémon (1) , Susanne F. Wampfler (8) , Peter Wurz (1, 8)

1 Physikalisches Institut [Bern]
2 PLANETO - LATMOS
3 CLaSP - Department of Climate and Space Sciences and Engineering
4 BIRA-IASB - Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique
5 IDA - Institute of Computer and Network Engineering [Braunschweig]
6 UTSA - The University of Texas at San Antonio
7 SwRI - Southwest Research Institute [San Antonio]
8 CSH - Center for Space and Habitability

The nucleus of the Jupiter-family comet 67P/Churyumov–Gerasimenko was discovered to be bi-lobate in shape when the European Space Agency spacecraft Rosetta first approached it in 2014 July. The bi-lobate structure of the cometary nucleus has led to much discussion regarding the possible manner of its formation and on how the composition of each lobe might compare with that of the other. During its two-year-long mission from 2014 to 2016, Rosetta remained in close proximity to 67P/Churyumov–Gerasimenko, studying its coma and nucleus in situ. Based on lobe-specific measurements of HDO and H2O performed with the ROSINA Double Focusing Mass Spectrometer (DFMS) on board Rosetta, the deuterium-to-hydrogen (D/H) ratios in water from the two lobes can be compared. No appreciable difference was observed, suggesting that both lobes formed in the same region and are homogeneous in their D/H ratios.

Domaines: Planète et Univers [physics]

Isaac R. H. G. Schroeder I, Kathrin Altwegg, Hans Balsiger, Jean-Jacques Berthelier, Michael R. Combi, et al.. A comparison between the two lobes of comet 67P/Churyumov-Gerasimenko based on D/H ratios in H₂O measured with the Rosetta/ROSINA DFMS. Monthly Notices of the Royal Astronomical Society, 2019, 489, pp.4734-4740. ⟨10.1093/mnras/stz2482⟩. ⟨insu-02189809⟩