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Spohn, T.; Knollenberg, J.; Ball, A. J.; Banaszkiewicz, M.; Benkhoff, J.; Grott, M.; Grygorczuk, J.; Hüttig, C.; Hagermann, A.; Kargl, G.; Kaufmann, E.; Kömle, N.; Kuhrt, E.; Kossacki, K. J.; Marczewski, W.; Pelivan, I.; Schrödter, R. and Seiferlin, K.
(2015).
DOI: https://doi.org/10.1126/science.aab0464
Abstract
Thermal and mechanical material properties determine comet evolution and even solar system formation because comets are considered remnant volatile-rich planetesimals. Using data from the Multipurpose Sensors for Surface and Sub-Surface Science (MUPUS) instrument package gathered at the Philae landing site Abydos on comet 67P/Churyumov-Gerasimenko, we found the diurnal temperature to vary between 90 and 130 K. The surface emissivity was 0.97, and the local thermal inertia was 85 ± 35 J m-2 K-1s-1/2. The MUPUS thermal probe did not fully penetrate the near-surface layers, suggesting a local resistance of the ground to penetration of >4 megapascals, equivalent to >2 megapascal uniaxial compressive strength. A sintered near-surface microporous dust-ice layer with a porosity of 30 to 65% is consistent with the data.