Dune-like features that were identified early in Rosetta’s mission in the neck region of Comet 67P/Churyumov–Gerasimenko were seen to evolve over the two years of study (first and last images). In addition, numerous circular scarp-like features were seen to develop and fade over time (central set of images). The circular features reached a diameter of 100 m in less than three months before subsequently fading away again, giving rise to a new set of ripples. The repeated development of these unique features at the same spot is thought to be linked to the curved structure of the neck region directing the flow of sublimating gas in a particular way.
The arrows point to the approximately location of the ripple and scarp features to help guide the eye between images when the viewing orientation and resolution changes.
The images were taken by Rosetta’s OSIRIS camera on 5 September 2014 (left), 25 April 2015 (centre top left), 10 May 2015 (centre top right), 11 July 2015 (centre bottom left), 20 December 2015 (centre bottom right), and 7 June 2016 (right). The image resolutions are 0.8, 1.6, 2.4, 2.9, 1.7 and 0.5 m/pixel, respectively.