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http://hdl.handle.net/20.500.12386/23145
Titolo: | Large heterogeneities in comet 67P as revealed by active pits from sinkhole collapse | Autori: | Vincent, Jean-Baptiste Bodewits, Dennis Besse, Sébastien Sierks, Holger Barbieri, Cesare Lamy, Philippe Rodrigo, Rafael Koschny, Detlef Rickman, Hans Keller, Horst Uwe Agarwal, Jessica A'Hearn, Michael F. Auger, Anne-Thérèse Barucci, M. Antonella Bertaux, Jean-Loup BERTINI, IVANO Capanna, Claire CREMONESE, Gabriele Da Deppo, Vania Davidsson, Björn Debei, Stefano de Cecco, Mariolino El-Maarry, Mohamed Ramy Ferri, Francesca FORNASIER, SONIA FULLE, Marco Gaskell, Robert GIACOMINI, LORENZA Groussin, Olivier Guilbert-Lepoutre, Aurélie Gutierrez-Marques, P. Gutiérrez, Pedro J. Güttler, Carsten Hoekzema, Nick Höfner, Sebastian Hviid, Stubbe F. Ip, Wing-Huen Jorda, Laurent Knollenberg, Jörg Kovacs, Gabor Kramm, Rainer Kührt, Ekkehard Küppers, Michael La Forgia, Fiorangela Lara, Luisa M. Lazzarin, Monica Lee, Vicky Leyrat, Cédric Lin, Zhong-Yi Lopez Moreno, Josè J. Lowry, Stephen Magrin, Sara Maquet, Lucie Marchi, Simone MARZARI, FRANCESCO MASSIRONI, MATTEO Michalik, Harald Moissl, Richard Mottola, Stefano Naletto, Giampiero Oklay, Nilda PAJOLA, MAURIZIO Preusker, Frank Scholten, Frank Thomas, Nicolas Toth, Imre TUBIANA, Cecilia |
Data pubblicazione: | 2015 | Rivista: | NATURE | Numero: | 523 | Fascicolo: | 7558 | Da pagina:: | 63 | Abstract: | Pits have been observed on many cometary nuclei mapped by spacecraft. It has been argued that cometary pits are a signature of endogenic activity, rather than impact craters such as those on planetary and asteroid surfaces. Impact experiments and models cannot reproduce the shapes of most of the observed cometary pits, and the predicted collision rates imply that few of the pits are related to impacts. Alternative mechanisms like explosive activity have been suggested, but the driving process remains unknown. Here we report that pits on comet 67P/Churyumov-Gerasimenko are active, and probably created by a sinkhole process, possibly accompanied by outbursts. We argue that after formation, pits expand slowly in diameter, owing to sublimation-driven retreat of the walls. Therefore, pits characterize how eroded the surface is: a fresh cometary surface will have a ragged structure with many pits, while an evolved surface will look smoother. The size and spatial distribution of pits imply that large heterogeneities exist in the physical, structural or compositional properties of the first few hundred metres below the current nucleus surface. <P /> | Acknowledgments: | OSIRIS was built by a consortium of the Max-Planck-Institut für Sonnensystemforschung, Katlenburg-Lindau, Germany, the CISAS, University of Padova, Italy, the Laboratoire d’Astrophysique de Marseille, France, the Instituto de Astrofísica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Técnica Aeroespacial, Madrid, Spain, the Universidad Politéchnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut für Datentechnik und Kommunikationsnetze der Technischen Universität Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is acknowledged. This work was also supported by NASA JPL contract 1267923 to the University of Maryland (M.F.A’H. and D.B.). M.F.A’H. is a Gauss Professor at the Akademie der Wissenschaften zu Göttingen and Max-Planck-Institut für Sonnensystemforschung (Germany). This research has made use of NASA’s Astrophysics Data System Bibliographic Services. We thank H. J. Melosh for reviews and criticism. | URI: | http://hdl.handle.net/20.500.12386/23145 | URL: | https://www.nature.com/articles/nature14564 | ISSN: | 0028-0836 | DOI: | 10.1038/nature14564 | Bibcode ADS: | 2015Natur.523...63V | Fulltext: | reserved |
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