image: Rosetta spacecraft images displaying large fractures both on a) the Big Lobe and b) the Small Lobe of comet 67P. view more
Credit: Image credit: Marco Franceschi and Luca Penasa.
A study finds features in comet 67P/Churyumov-Gerasimenko that illuminate the mechanical properties of materials that formed the comet, showing how the comet's structure was shaped. The comet 67P is bilobate, meaning that it consists of two lobes and was likely formed by collision of two cometesimals. The lobes display a concentric layered structure and are made of highly porous materials. Marco Franceschi and colleagues used high-resolution imaging of the comet, derived from the Rosetta spacecraft, and constructed 3D models of the layered structure to identify deformations such as folds in the layers and large fractures. Such features indicated that impact-related stress was felt throughout the nucleus and was globally accommodated through brittle plastic deformation rather than through compaction. Three-dimensional modeling further suggested that the impact produced significant mass loss and occurred between two roughly ellipsoidal bodies that compressed in the direction of the collision and elongated perpendicularly to it. According to the authors, the results suggest a revised model of the rheology of cometesimals that requires the binding action of water ice as well as organic material.
Article #19-14552: "Global-scale brittle plastic rheology at the cometesimals merging of comet 67P/Churyumov- Gerasimenko," by Marco Franceschi et al.
MEDIA CONTACT: Marco Franceschi, University of Trieste, ITALY; e-mail: mfranceschi@units.it
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Journal
Proceedings of the National Academy of Sciences