Boulder Cheops on Comet 67P/Churyumov-Gerasimenko
The scientific imaging system OSIRIS on board ESA’s spacecraft Rosetta has caught a spectacular glimpse of one of the many boulders that cover the surface of comet 67P/Churyumov-Gerasimenko.
The scientific imaging system OSIRIS on board ESA’s spacecraft Rosetta has caught a spectacular glimpse of one of the many boulders that cover the surface of comet 67P/Churyumov-Gerasimenko.
The boulder-like structures that Rosetta has revealed in many places on the surface of 67P/C-G are one of the comet’s most striking and mysterious features .
Just like the many other boulders seen by both OSIRIS and the spacecraft’s NAVCAM, Cheops stands out not just physically, but also as a slightly brighter feature compared to the darker surface around it.
OSIRIS Principal Investigator Holger Sierks, from the Max Planck Institute for Solar System Research (MPS) in Germany, describes the surface of Cheops as “very craggy and irregular.”
Interspersed between the lighter lumps on the boulder’s surface are intriguing small patches of darker material, similar in brightness and texture to the ground upon which the boulder lies.
“It almost looks as if loose dust covering the surface of the comet has settled in the boulder’s cracks. But, of course, it is much too early to be sure,” says Sierks.
Apart from their size distribution, which is being measured through careful analysis of the images, almost all other properties of 67P/C-G’s boulders are still a mystery to researchers. What are they made of? What are their physical properties, including density and stability? How were they created? As Rosetta continues to survey and monitor the comet’s surface in the next months, the scientists will be looking for clues.
“For example, if the boulders are exposed by cometary activity or are displaced following the comet’s gravity field, we should be able to track this down in our images,” adds Sierks.
Tomorrow, Rosetta will begin its Close Observation Phase reaching a distance of only 10 kilometres from the comet’s surface, giving the cameras an even closer view of these features
