Thermal fracturing on comets : Applications to 67P/Churyumov-Gerasimenko
We simulate the stresses induced by temperature changes in a putative hard layer near the surface of comet 67P/Churyumov-Gerasimenko with a thermo-viscoelastic model. Such a layer could be formed by the recondensation or sintering of water ice (and dust grains), as suggested by laboratory experiment...
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ftpubman:oai:pure.mpg.de:item_2574138 2023-08-27T04:09:57+02:00 Thermal fracturing on comets : Applications to 67P/Churyumov-Gerasimenko Attree, N. Groussin, O. Jorda, L. Rodionov, S. Auger, A. Thomas, N. Brouet, Y. Poch, O. Kührt, E. Knapmeyer, M. Preusker, F. Scholten, F. Knollenberg, J. Hviid, S. Hartogh, P. 2018 http://hdl.handle.net/21.11116/0000-0001-1BCB-D eng eng info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201731937 http://hdl.handle.net/21.11116/0000-0001-1BCB-D Astronomy and Astrophysics ROSETTA: MIRO info:eu-repo/semantics/article 2018 ftpubman https://doi.org/10.1051/0004-6361/201731937 2023-08-02T00:22:00Z We simulate the stresses induced by temperature changes in a putative hard layer near the surface of comet 67P/Churyumov-Gerasimenko with a thermo-viscoelastic model. Such a layer could be formed by the recondensation or sintering of water ice (and dust grains), as suggested by laboratory experiments and computer simulations, and would explain the high compressive strength encountered by experiments on board the Philae lander. Changes in temperature from seasonal insolation variation penetrate into the comet’s surface to depths controlled by the thermal inertia, causing the material to expand and contract. Modelling this with a Maxwellian viscoelastic response on a spherical nucleus, we show that a hard, icy layer with similar properties to Martian permafrost will experience high stresses: up to tens of MPa, which exceed its material strength (a few MPa), down to depths of centimetres to a metre. The stress distribution with latitude is confirmed qualitatively when taking into account the comet’s complex shape but neglecting thermal inertia. Stress is found to be comparable to the material strength everywhere for sufficient thermal inertia (≳50 J m −2 K −1 s −1∕2 ) and ice content (≳45% at the equator). In this case, stresses penetrate to a typical depth of ~0.25 m, consistent with the detection of metre-scale thermal contraction crack polygons all over the comet. Thermal fracturing may be an important erosion process on cometary surfaces which breaks down material and weakens cliffs. Article in Journal/Newspaper Ice permafrost Max Planck Society: MPG.PuRe Astronomy & Astrophysics 610 A76 |
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English |
topic |
ROSETTA: MIRO |
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ROSETTA: MIRO Attree, N. Groussin, O. Jorda, L. Rodionov, S. Auger, A. Thomas, N. Brouet, Y. Poch, O. Kührt, E. Knapmeyer, M. Preusker, F. Scholten, F. Knollenberg, J. Hviid, S. Hartogh, P. Thermal fracturing on comets : Applications to 67P/Churyumov-Gerasimenko |
topic_facet |
ROSETTA: MIRO |
description |
We simulate the stresses induced by temperature changes in a putative hard layer near the surface of comet 67P/Churyumov-Gerasimenko with a thermo-viscoelastic model. Such a layer could be formed by the recondensation or sintering of water ice (and dust grains), as suggested by laboratory experiments and computer simulations, and would explain the high compressive strength encountered by experiments on board the Philae lander. Changes in temperature from seasonal insolation variation penetrate into the comet’s surface to depths controlled by the thermal inertia, causing the material to expand and contract. Modelling this with a Maxwellian viscoelastic response on a spherical nucleus, we show that a hard, icy layer with similar properties to Martian permafrost will experience high stresses: up to tens of MPa, which exceed its material strength (a few MPa), down to depths of centimetres to a metre. The stress distribution with latitude is confirmed qualitatively when taking into account the comet’s complex shape but neglecting thermal inertia. Stress is found to be comparable to the material strength everywhere for sufficient thermal inertia (≳50 J m −2 K −1 s −1∕2 ) and ice content (≳45% at the equator). In this case, stresses penetrate to a typical depth of ~0.25 m, consistent with the detection of metre-scale thermal contraction crack polygons all over the comet. Thermal fracturing may be an important erosion process on cometary surfaces which breaks down material and weakens cliffs. |
format |
Article in Journal/Newspaper |
author |
Attree, N. Groussin, O. Jorda, L. Rodionov, S. Auger, A. Thomas, N. Brouet, Y. Poch, O. Kührt, E. Knapmeyer, M. Preusker, F. Scholten, F. Knollenberg, J. Hviid, S. Hartogh, P. |
author_facet |
Attree, N. Groussin, O. Jorda, L. Rodionov, S. Auger, A. Thomas, N. Brouet, Y. Poch, O. Kührt, E. Knapmeyer, M. Preusker, F. Scholten, F. Knollenberg, J. Hviid, S. Hartogh, P. |
author_sort |
Attree, N. |
title |
Thermal fracturing on comets : Applications to 67P/Churyumov-Gerasimenko |
title_short |
Thermal fracturing on comets : Applications to 67P/Churyumov-Gerasimenko |
title_full |
Thermal fracturing on comets : Applications to 67P/Churyumov-Gerasimenko |
title_fullStr |
Thermal fracturing on comets : Applications to 67P/Churyumov-Gerasimenko |
title_full_unstemmed |
Thermal fracturing on comets : Applications to 67P/Churyumov-Gerasimenko |
title_sort |
thermal fracturing on comets : applications to 67p/churyumov-gerasimenko |
publishDate |
2018 |
url |
http://hdl.handle.net/21.11116/0000-0001-1BCB-D |
genre |
Ice permafrost |
genre_facet |
Ice permafrost |
op_source |
Astronomy and Astrophysics |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201731937 http://hdl.handle.net/21.11116/0000-0001-1BCB-D |
op_doi |
https://doi.org/10.1051/0004-6361/201731937 |
container_title |
Astronomy & Astrophysics |
container_volume |
610 |
container_start_page |
A76 |
_version_ |
1775351634497372160 |