Elemental and molecular abundances in comet 67P/Churyumov-Gerasimenko

Martin Rubin (1) , Kathrin Altwegg (1) , Hans Balsiger (1) , Jean-Jacques Berthelier (2) , Michael Combi (3) , Johan De keyser (4) , Maria Drozdovskaya (5) , Björn Fiethe (6) , Stephen Fuselier (7) , Sébastien Gasc (1) , Tamas Gombosi (3) , Nora Hänni (8) , Kenneth Hansen (3) , Urs Mall (9) , Henri Rème (10) , Isaac Schroeder (1) , Markus Schuhmann (1) , Thierry Sémon (1) , Jack Waite (7) , Susanne Wampfler (5) , Peter Wurz (5, 1)

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 CSH - Center for Space and Habitability
6 IDA - Institute of Computer and Network Engineering [Braunschweig]
7 SwRI - Southwest Research Institute [San Antonio]
8 WP - Space Research and Planetary Sciences [Bern)
9 MPS - Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research
10 IRAP - Institut de recherche en astrophysique et planétologie

Comets are considered to be some of the most pristine and unprocessed Solar system objects accessible to in situ exploration. Investigating their molecular and elemental composition takes us on a journey back to the early period of our Solar system and possibly even further. In this work, we deduce the bulk abundances of the major volatile species in comet 67P/Churyumov-Gerasimenko, the target of the European Space Agency’s (ESA) Rosetta mission. The basis are measurements obtained with the ROSINA instrument suite on board the Rosetta orbiter during a suitable period of high outgassing near perihelion. The results are combined with both gas and dust composition measurements published in the literature. This provides an integrated inventory of the major elements present in the nucleus of 67P/Churyumov-Gerasimenko. Similar to comet 1P/Halley, which was visited by ESA’s Giotto spacecraft in 1986, comet 67P/Churyumov-Gerasimenko also shows near-solar abundances of oxygen and carbon, whereas hydrogen and nitrogen are depleted compared to solar. Still, the degree of devolatilization is lower than that of inner Solar system objects, including meteorites and the Earth. This supports the idea that comets are amongst the most pristine objects in our Solar system.

Domaines: Planète et Univers [physics]

Martin Rubin, Kathrin Altwegg, Hans Balsiger, Jean-Jacques Berthelier, Michael Combi, et al.. Elemental and molecular abundances in comet 67P/Churyumov-Gerasimenko. Monthly Notices of the Royal Astronomical Society, 2019, 489 (1), pp.594-607. ⟨10.1093/mnras/stz2086⟩. ⟨insu-02343210⟩