Meter-scale thermal contraction crack polygons on the nucleus of comet 67P/Churyumov-Gerasimenko

摘要

Highlights?Polygonal morphologies with a mean size of 3.0?m are reported on the nucleus of comet 67P.?Polygons are consistent with thermal contraction crack polygons known on Earth and Mars.?They imply a consolidated sintered layer of water ice, located a few cm below the surface.?Polygons are young surface morphologies and could be as young as a few orbital periods.AbstractWe report on the detection and characterization of more than 6300 polygons on the surface of the nucleus of comet 67P/Churyumov-Gerasimenko, using images acquired by the OSIRIS camera onboard Rosetta between August 2014 and March 2015. They are found in consolidated terrains and grouped in localized networks. They are present at all latitudes (from North to South) and longitudes (head, neck, and body), sometimes on pit walls or following lineaments. About 1.5% of the observed surface is cover