Simulations of impact features on comet 67P/Churyumov-Gerasimenko, as imaged by OSIRIS/ROSETTA

Abstract:

The images obtained by OSIRIS on board the ESA Rosetta mission during the approaching phase and during the orbit around the nucleus of the comet 67P/Churyumov-Gerasimenko allowed to map the cometary surface with the very high resolution of the Narrow Angle Camera (NAC). Further important products have been realized with the nucleus images as the shape model and the Digital Terrain Model allowing to derive the profile of some features possibly identified as impact craters.

Impact craters have been simulated with the iSALE hydrocode, one of the multi-rheology and multi-material extension of the SALE hydrocode (Amsden et al., 1980, Collins et al., 2004; Wünnemann et al., 2006), specifically developed to model impact crater formation.

The structure and composition of the projectile was simplified to spherical and homogeneous dunite impacting at an angle of 90°, while we have assumed different target composition from dunite to water ice changing the porosity and the strength. A further important parameter to take into account is the temperature of the region where the crater is formed and we will adopt an updated thermal model of the nucleus in order to better define it.

We will show the preliminary results of the impact simulations performed in 2D, including some insights on the nucleus structure.

Acknowledgements

We gratefully acknowledge the developers of iSALE-2D, including Gareth Collins, Kai Wünnemann, Dirk Elbeshausen, Boris Ivanov and Jay Melosh (see www.iSALE-code.de).