COMETARY SCIENCE. Thermal and mechanical properties of the near-surface layers of comet 67P/Churyumov-Gerasimenko

T Spohn; J Knollenberg; A J Ball; M Banaszkiewicz; J Benkhoff; M Grott; J Grygorczuk; C Hüttig; A Hagermann; G Kargl; E Kaufmann; N Kömle; E Kührt; K J Kossacki; W Marczewski; I Pelivan; R Schrödter; K Seiferlin

doi:10.1126/science.aab0464

COMETARY SCIENCE. Thermal and mechanical properties of the near-surface layers of comet 67P/Churyumov-Gerasimenko

Science. 2015 Jul 31;349(6247):aab0464. doi: 10.1126/science.aab0464.

Authors

T Spohn¹, J Knollenberg², A J Ball³, M Banaszkiewicz⁴, J Benkhoff³, M Grott², J Grygorczuk⁴, C Hüttig², A Hagermann⁵, G Kargl⁶, E Kaufmann⁵, N Kömle⁶, E Kührt², K J Kossacki⁷, W Marczewski⁴, I Pelivan², R Schrödter², K Seiferlin⁸

Affiliations

¹ Institute of Planetary Research, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Berlin, Germany. tilman.spohn@dlr.de.
² Institute of Planetary Research, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Berlin, Germany.
³ European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Noordwijk, Netherlands.
⁴ Space Research Center, Warsaw, Poland.
⁵ Department of Physical Sciences, The Open University, Milton Keynes, UK.
⁶ Space Research Institute, Austrian Academy of Sciences Graz, Austria.
⁷ Faculty of Physics, University of Warsaw, Warsaw, Poland.
⁸ Physics Institute, University of Berne, Berne, Switzerland.

PMID: 26228152
DOI: 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(-1)s(-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.

Publication types

Research Support, Non-U.S. Gov't