Europlanet Science Congress 2020
Virtual meeting
21 September – 9 October 2020
Europlanet Science Congress 2020
Virtual meeting
21 September – 9 October 2020

Poster presentations and abstracts


The goal of this session is to cover numerical simulations and relevant laboratory investigations related to the Small Bodies (comets, KBOs, rings, asteroids, meteorites, dust), their formation and evolution, and the instruments of their exploration. This session is specially focused on the interdisciplinary approach in the development of models (formal descriptions of physical phenomena), experiments (on ground and in micro-gravity), and mathematical simulations (computational methods and algorithms of solution) of various astrophysical phenomena: (i) dusty gas cometary atmospheres; (ii) volcanic activity on icy satellites (e.g. Enceladus and Io); (iii) planetary body formation (e.g. via pebbles growth), and planetesimal dynamics.

This session will include an introduction and discussion of new and/or existing laboratory studies in simulated space-like environments and models, experimental techniques, computational methods that can address the results of analytical,experimental and numerical analysis (with respect to computational methods and algorithms of solution) on the above described studies.
Abstracts on thermophysical evolution models of small bodies interiors as well as on the modeling of atmosphere and exosphere are welcome.

Conveners: Stavro Lambrov Ivanovski, Vladimir Zakharov | Co-conveners: Vincenzo Della Corte, Michelangelo Formisano, Marco Fulle, Raphael Marschall, Luis Diego Pinto, Alessandra Rotundi, Diego Turrini

Session assets

Session summary

Chairperson: Stavro Ivanovski
Nicholas Attree, Laurent Jorda, Olivier Groussin, and Raphael Marschall

Cometary outgassing produces a back-reaction force on a nucleus that can alter its trajectory and rotation state. Understanding this activity is key to exploring the physics of the upper layers of cometary surfaces, with implications for their formation and subsequent evolutionary history, and can be constrained by observing the orbit and rotation changes. For comet 67P/Churyumov-Gerasimenko, detailed measurements have been made by the Rosetta spacecraft and various attempts have been made to model the activity (see, e.g. [1,2]).

Here we will present updated work using the activity model of [2] to fit to Rosetta outgassing, trajectory, and rotation data. We test a number of different activity distributions over the surface of the comet by varying the Effective Active Fraction (EAF), relative to pure water ice, of facets on a shape model. The previous work has shown that, in order to fit the fast ramp-up and fall-off in outgassing either side of perihelion, 67P’s EAF must vary with time. We therefore investigate a number of different EAF curves to see if different parametric models can be ruled out. The objective here is to constraint the shape of the activity curve that a more advanced thermo-physical model (see, for example [3,4]) must produce in order to fit the data. We also investigate different spatial patterns in EAF, and attempt to correlate them to physical features on the cometary surface. Here we are able, for the first time, to achieve a good fit to the Rosetta data by parameterizing EAF in terms of the different geological unit types on 67P (Fig. 1). This may have important implications for understanding how activity works on the different types of surface observed on cometary nuclei, including ‘rough’, ‘smooth’, ‘dusty’ and ‘rocky’ surface morphologies. Finally, in addition to the changes in rotation period examined in [2], we also compute changes in the rotation axis in order to compare with the observations.


How to cite: Attree, N., Jorda, L., Groussin, O., and Marschall, R.: Further constraints on activity models of comet 67P/Churyumov-Gerasimenko with Rosetta data, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-99,, 2020.