Editor's note: To see our latest news of Rosetta's comet encounter, visit: Rosetta, Europe's Comet-Chaser: Latest News, Images and Video.
Images taken by a European probe en route to link up with a comet, have revealed a striking feature of the target comet coming into view.
Photos of comet 67P/Churyumov-Gerasimenko captured by the European Space Agency's Rosetta mission reveal the comet's "neck." The pictures suggest that something interesting is going on in the connecting link between the smaller head and the larger body of the comet.
"The only thing we know for sure at this point is that this neck region appear brighter compared to the head and body of the nucleus," Holger Sierks, of the Max Planck Institute for Solar System Research in Germany, said in a statement. [Photos: Europe's Rosetta Comet Mission in Pictures]
Sierks is the principle investigator for the OSIRIS instrument responsible for capturing the images.
The intensity difference could be caused by different materials, or by a variation in the sizes of the dust and ice grains that compose the comet. A topographical effect could also be responsible for the contrast.
A 2010 flyby of comet 103P/Hartley, visited by NASA's EPOXI mission, suggests a third possibility. Scientists think that comet Hartley's variations in surface texture are caused by a gravitational low in its middle, which captures material ejected from the surface of the comet's nucleus. A similar gravity well could exist around the neck of comet 67P.
Captured at a distance of 3,400 miles (5,500 kilometers), Rosetta's images have a resolution of 330 feet (100 meters) per pixel. As the spacecraft closes in on the comet in preparation for its August 6 rendezvous with the comet, the OSIRIS team hopes to study the light reflected from the comet's surface to identify its material composition.
Using the camera images, the team is also modeling the comet's three-dimensional shape. This data will not only help improve the understanding of comets, but also allow scientists to select a landing site for the Philae lander currently scheduled to touch down on the comet on November 11th.
Rosetta will be the first mission in history to rendezvous with a comet, travel with it around the sun, and send a lander to its surface. It will remain in orbit until the nominal mission end in December 2015.