This project builds on

• the successful evaluation and modelling of Rosetta data initiated through previous SNSF grants and the H2020 funded project, MiARD
• the successful selection (with our participation) of the Europa Imaging System for Europa Clipper
• the ability to study and characterize potential habitats within our Solar System using current (e.g. Trace Gas Orbiter) and future (e.g. Europa Clipper) remote-sensing instrumentation and laboratory experiments.

Gas dynamics modelling of 67P

We are extending our gas dynamics modelling to include species other than water and attempt to constrain source regions of specific molecules. This will lead to better understanding of nucleus
inhomogeneity. We are currently looking at CO2 emission from the nightside to explain rather low dayside to nightside dust asymmetry ratios in the innermost coma.

Dust dynamics modelling of 67P

We are studying the behavior of dust in the vicinity of the nucleus including evidence for deviations
from force-free radial outflow through analyses of Rosetta/OSIRIS data and linking this to gas dynamics modelling
following the approach of Marschall et al. (2016). The evidence for nightside activity has been strengthened by
our analysis and suggests that CO2 and/or CO are major drivers of dust emission. This is also being linked to observations
of other comets such as Halley and Borrelly.

Chemical modelling of 67P

We are using a model by Marbouef et al. (2012) in collaboration with Olivier Mousis (LAM) to see if the 1D chemical models are also
able to reproduce the trends seen in ROSINA data. The current work suggests that dust mantles are necessary to depress the temporal variability of
CO2 and CO.

We have also been looking at how future missions could be franed to try to address the uncertainties we have seen in the modelling work.

Recent papers published

Marschall, R., L. Rezac, D. Kappel, C.~C. Su, S.-B. Gerig, M. Rubin, O. Pinz{‘o}n-Rodr{’\i}guez, D. Marshall, Y. Liao, C. Herny, G. Arnold, C. Christou, S.~K. Dadzie, O. Groussin, P. Hartogh, L. Jorda, E. K{“u}hrt, S. Mottola, O. Mousis, F. Preusker, F. Scholten, P. Theologou, J.-S. Wu, K. Altwegg, R. Rodrigo, and N. Thomas,(2019),A comparison of multiple Rosetta data sets and 3D model calculations of 67P/Churyumov-Gerasimenko coma around equinox (May 2015),Icarus,328,104%-\P.
Thomas, N., S. Ulamec, E. K{“u}hrt, V. Ciarletti, B. Gundlach, Z. Yoldi, G. Schwehm, C. Snodgrass, and S.~F. Green,(2019),Towards New Comet Missions,Space Science Reviews,215,47%-\P.

There are currently two papers on this subject in preparation.