Vol. 591
In section 10. Planets and planetary systems

Electrical properties and porosity of the first meter of the nucleus of 67P/Churyumov-Gerasimenko.

by A. Lethuillier, A. Le Gall, M. Hamelin, et al. A&A 591, A32


On November 12, 2014, the Philae module sent by the ESA Rosetta spacecraft landed on the surface of comet 67P/Churyumov-Gerasimenko. At a distance of 2.99 au from the Sun. Lethullier et al. analyzed the results obtained by the Permittivity Probe SESAME-PP onboard Philae which measured for the first time the low frequency dielectric properties of the first meter of a comet nucleus. The data show that this surface layer is much less porous than the deeper interior of the comet (which had been probed previously by another instrument, the CONSERT bi-static radar onboard the Rosetta orbiter). This shows that the surface layer of the comet probably consists of a sintered dust-ice layer over an extremely porous interior.