What CONSERT measurements tell us about the interior of the 67/C-G comet ?
Résumé
The structure of the nucleus is one of major unknown in the cometary science. The scientific objectives of the Comet Nucleus Sounding Experiment by Radiowave Transmission (CONSERT) aboard ESA spacecraft Rosetta are to perform an interior characterization of comet 67P/Churyumov-Gerasimenko nucleus. This is done by means of a bi-static sounding between the lander Philae launched on the comet’s surface and the obiter Rosetta. During the first night after Philae landing CONSERT operated during 9 hours and have made the measurements through the small lobe (head) of the 67P/ C-G. We will describe measurements that explored the interior of the comet, discuss results and their interpretation in term of the internal structure. The analyses and interpretation have been done using the form of the received signals and then 2D and 3D modelling of the signal that propagated through the comet. This led us to conclusions that the comet is homogenous on the scale of the ten of wavelengths and perhaps slowly variable with the dielectric constant decreasing into interior of the comet. The measured value 1.27 +- 0.05 of the average dielectric constant permit us to interpret the composition of the materials in terms of porosity, dust to ice ratio and possible materials (Kofman et al, Science 2015, Ciarletti et al, A&A, 2015). In this presentation we will discuss all these results.