The oxygen isotopic composition (18O/16O) in the dust of comet 67P/Churyumov-Gerasimenko measured by COSIMA on-board Rosetta

John Paquette (1) , C. Engrand (2) , J Hilchenbach (1) , C Fray (3) , J Stenzel (1) , J Silen (4) , J Rynö (4) , J Kissel (1) , The Cosima Team (5)

1 MPS - Max-Planck-Institut für Sonnensystemforschung
2 CSNSM - Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse
3 LISA (UMR_7583) - Laboratoire Interuniversitaire des Systèmes Atmosphériques
4 FMI - Finnish Meteorological Institute
5 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace

The oxygen isotopic ratio 18O/16O has been measured in cometary gas for a wide variety of comets, but the only measurements in cometary dust were performed by the Stardust cometary sample return mission. Most such measurements find a value of the ratio that is consistent with Vienna Standard Mean Ocean Water (VSMOW) within errors. In this work we present the result of a measurement, using the COSIMA (the COmetary Secondary Ion Mass Analyser) instrument on the Rosetta orbiter, of the oxygen isotopic ratio in dust from Comet 67P/Churyumov-Gerasimenko. Measuring the 18O/16O ratio with COSIMA is challenging for a number of reasons, but it is possible with a reasonable degree of precision. We find a result of 2.00 × 10−3 ± 1.2 × 10−4, which is consistent within errors with VSMOW.

Keywords: comets: general – comets: individual: 67P/Churyumov-Gerasimenko – planetary systems.

Domains: Sciences of the Universe [physics]

John Paquette, C. Engrand, J Hilchenbach, C Fray, J Stenzel, et al.. The oxygen isotopic composition (18O/16O) in the dust of comet 67P/Churyumov-Gerasimenko measured by COSIMA on-board Rosetta. Monthly Notices of the Royal Astronomical Society, 2018, 477 (3), pp.3836-3844. ⟨10.1093/mnras/sty560⟩. ⟨insu-02002394⟩