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Citation

Spohn T, Knollenberg J, Ball AJ, Banaszkiewicz M, Benkhoff J, Grott M, Grygorczuk J, Hüttig C, Hagermann A, Kargl G, Kaufmann E, K?mle N, Kührt E, Kossacki KJ & Marczewski W (2015) Thermal and mechanical properties of the near-surface layers of comet 67P/Churyumov-Gerasimenko. Science, 349 (6247), Art. No.: aab0464. 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.

Notes
Additional co-authors: I. Pelivan, R. Schr?dter, K. Seiferlin

Journal
Science: Volume 349, Issue 6247