Year: 2018
Type: article
Abstract: We directly measured twenty overhanging cliffs on the surface of comet 67P/Churyumov–Gerasimenko extracted from the latest shape model and estimated the minimum tensile strengths needed to support them against collapse under the comet’s gravity. We find extremely low strengths of around 1 Pa or less (1 to 5 Pa, when scaled to a metre length). The presence of eroded material at the base of most overhangs, as well as the observed collapse of two features andthe implied previous collapse of another, suggests that they are prone to failure and that the true material strengths are close to these lower limits (although we only consider static stresses and not dynamic stress from, for example, cometary activity). Thus, a tensile strength of a few pascals is a good approximation for the tensile strength of the 67P nucleus material, which is in agreement with previous work. We find no particular trends in overhang properties either with size over the ~10–100 m range studied here or location on the nucleus. There are no obvious differences, in terms of strength, height or evidence of collapse, between the populations of overhangs on the two cometary lobes, suggesting that 67P is relatively homogenous in terms of tensile strength. Low material strengths are supportive of cometary formation as a primordial rubble pile or by collisional fragmentation of a small body (tens of km).
Source: Astronomy and Astrophysics
Authors: N. Attree, O. Groussin, L. Jorda, D. Nébouy, N. Thomas, Y. Brouet, E. Kührt, F. Preusker, F. Scholten, J. Knollenberg, P. Hartogh, H. Sierks, C. Barbieri, P. Lamy, R. Rodrigo, D. Koschny, H. Rickman, H. U. Keller, M. F. A’Hearn, A.-T. Auger, M. A. Barucci, J.-L. Bertaux, I. Bertini, D. Bodewits, S. Boudreault, G. Cremonese, V. Da Deppo, B. Davidsson, S. Debei, M. De Cecco, J. Deller, M. R. El-Maarry, S. Fornasier, M. Fulle, P. J. Gutiérrez, C. Güttler, S. Hviid, W.-H. Ip, G. Kovacs, J. R. Kramm, M. Küppers, L. M. Lara, M. Lazzarin, J. J. Lopez Moreno, S. Lowry, S. Marchi, F. Marzari, S. Mottola, G. Naletto, N. Oklay, M. Pajola, I. Toth, C. Tubiana, J.-B. Vincent, X. Shi
Institutions: Centre National de la Recherche Scientifique, Aix-Marseille Université, Laboratoire d’Astrophysique de Marseille, University of Bern, Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR), Max Planck Institute for Solar System Research, University of Padua, Laboratoire atmosphères, milieux, observations spatiales, Consejo Superior de Investigaciones Científicas, Centro de Astrobiología, International Space Science Institute, European Space Agency, European Space Research and Technology Centre, Centrum Badań Kosmicznych, Uppsala University, Polish Academy of Sciences, Technische Universität Braunschweig, University of Maryland, College Park, Laboratoire d’études spatiales et d’instrumentation en astrophysique, Université Paris Diderot, Université de Versailles Saint-Quentin-en-Yvelines, Institut Pierre-Simon Laplace, Trieste Astronomical Observatory, National Institute for Astrophysics, University of Trento, Instituto de Astrofísica de Andalucía, National Central University, European Space Astronomy Centre, University of Kent, South East Physics Network, Southwest Research Institute, Solar System Exploration Research Virtual Institute, Ames Research Center, Konkoly Observatory, HUN-REN Research Centre for Astronomy and Earth Sciences
Language: English
Topic: Astro and Planetary Science
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $754
Awards: Multi-instrument analysis of Rosetta data - Establishing a new paradigm for cometary activity, G434337789, Multi-instrument analysis of Rosetta data – Establishing a new paradigm for cometary activity, G8854643033, Multi-instrument analysis of Rosetta data - Establishing a new paradigm for cometary activity
OpenAlex ID: W2779084073