Studying the surface of a comet is challenging as the nucleus is either too far to be resolved in details, or it is close enough but
its own activity hides all the features we would like to investigate.
One of the topic of interest is the localization of active regions on the surface. Although this can be done from a spacecraft, the
jets of gas and dust represent a hazard for any probe passing at close distance from the nucleus and any hint on the local activity
should be taken into consideration to constrain the approach.
Comet 67P/Churyumov-Gerasimenko on 06 August 2014
(Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA)
My cometary work is based on observations, analysis, and simulations of dust coma structures: patterns embedded in the coma and considered
as signatures of active dust emitting regions at the surface of the nucleus. I developped the scientific software COSSIM
to simulate the emission of these dust jets from a realistic physical model of cometary nuclei and reproduce the images acquired with ground or space based observations.
Our model includes a flexible 3D representation of the nucleus and a physical description of the dust acceleration processes in its neighborhood.
The model have been succesfully used to constrain the spin axis orientation and activity of several targets : 73P/Schwassmann-Wachmann 3-B,C, 9P/Tempel 1, 81P/Wild 2, 67P/Churyumov-Gerasimenko. For the two first studies (9P & 81P), our results could be directly compared with in-situ measurements from the spacecrafts Deep Impact and Stardust and in both cases there were in very good agreement. For the latter case (67P) we have analysed and simulated the activity over the last two perihelion passages, and made predictions on what the Rosetta mission is going to observe in 2014-2015.
COma Structures SIMulator (COSSIM)
Dust jets of comet 9P/Tempel 1