The Rosetta space probe (from the European Space Agency) has been orbiting comet 67P / Churiumov-Guerasimenko since August 2014, providing us with data on the comet’s surface and composition.
Now, a new study carried out by scientists from the National Institute of Astrophysics of Italy (INAF) and led by Gianrico Filacchione of the Institute of Astrophysics and Space Planetology in Rome (Italy), has confirmed that in the comet there is not only trace of small ice crystals, but there are large areas of frozen water in at least two ravines in the region named Imhotep (in honor of the great Egyptian architect and astronomer).
The researchers have detected, thanks to the new data provided by the VIRTIS-M instrument on board the ESA space probe, that both at the base of both ravines and on the walls of the same, there is a nearby external ice layer one millimeter thick and another smaller than 50 microns – mixed with dark material -, again showing that water is one of the most abundant components of the comet’s nucleus. The area where the icy water grains have been observed is marked in ESA photographs with a yellow and a white arrow.
According to the work, the largest grains may have arisen from an occasional exposure, and their consequent evaporation, of the more abundant ice layers of the comet’s nucleus or perhaps by the fusion of smaller grains.
The study has been published in the journal Nature.
