Large heterogeneities in comet 67P as revealed by active pits from sinkhole collapse

Jean Baptiste Vincent, Dennis Bodewits, Sébastien Besse, Holger Sierks, Cesare Barbieri, Philippe Lamy, Rafael Rodrigo, Detlef Koschny, Hans Rickman, Horst Uwe Keller, Jessica Agarwal, Michael F. A'Hearn, Anne Thérèse Auger, M. Antonella Barucci, Jean Loup Bertaux, Ivano Bertini, Claire Capanna, Gabriele Cremonese, Vania Da Deppo, Björn DavidssonStefano Debei, Mariolino De Cecco, Mohamed Ramy El-Maarry, Francesca Ferri, Sonia Fornasier, Marco Fulle, Robert Gaskell, Lorenza Giacomini, Olivier Groussin, Aurélie Guilbert-Lepoutre, P. Gutierrez-Marques, Pedro J. Gutiérrez, Carsten Güttler, Nick Hoekzema, Sebastian Höfner, Stubbe F. Hviid, Wing Huen Ip, Laurent Jorda, Jörg Knollenberg, Gabor Kovacs, Rainer Kramm, Ekkehard Kührt, Michael Küppers, Fiorangela La Forgia, Luisa M. Lara, Monica Lazzarin, Vicky Lee, Cédric Leyrat, Zhong Yi Lin, Josè J. Lopez Moreno, Stephen Lowry, Sara Magrin, Lucie Maquet, Simone Marchi, Francesco Marzari, Matteo Massironi, Harald Michalik, Richard Moissl, Stefano Mottola, Giampiero Naletto, Nilda Oklay, Maurizio Pajola, Frank Preusker, Frank Scholten, Nicolas Thomas, Imre Toth, Cecilia Tubiana

Research output: Contribution to journalArticlepeer-review

129 Scopus citations

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.

Original languageEnglish
Pages (from-to)63-66
Number of pages4
JournalNature
Volume523
Issue number7558
DOIs
StatePublished - 1 Jul 2015

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