Three faces of a comet

New images of comet 67P/Churyumov-Gerasimenko reveal an irregular shape.

The nucleus of comet 67P/Churyumov-Gerasimenko is an irregularly shaped body as seen from ESA’s spacecraft Rosetta. New images of the comet obtained by OSIRIS, the onboard scientific imaging system, reveal a unique shape. The tiny world that is quickly growing bigger as Rosetta approaches its destination seems to display three prominent structures.

“From what we can discern in these early images, 67P is an irregularly looking body”, says OSIRIS Principal Investigator Holger Sierks from the Max Planck Institute for Solar System Research (MPS) in Germany. The current images were taken on July 4th, 2014 from a distance of approximately 37000 kilometers. Even though the body covers only about 30 pixels, the images suggest what looks like three large structures or a deep depression.

Irregular, elongated, and structured shapes are not uncommon for small bodies such as asteroids and comets. Of the five cometary nuclei that have been visited by spacecraft in close flybys so far, all are far from spherical. Comet 103P/Hartley, for example, is a long-stretched body resembling a juggling club. “Seeing 67P now slowly revealing its own unique features is an unprecedented adventure”, says OSIRIS scientist Jean-Baptiste Vincent from the MPS.

Rosetta is an ESA mission with contributions from its member states and NASA. Rosetta's Philae lander is provided by a consortium led by DLR, MPS, CNES and ASI. Rosetta will be the first mission in history to rendezvous with a comet, escort it as it orbits the Sun, and deploy a lander to its surface.

The scientific imaging system OSIRIS was built by a consortium led by the Max Planck Institute for Solar System Research (Germany) in collaboration with CISAS, University of Padova (Italy), the Laboratoire d'Astrophysique de Marseille (France), the Instituto de Astrofísica de Andalucia, CSIC (Spain), the Scientific Support Office of the European Space Agency (The Netherlands), the Instituto Nacional de Técnica Aeroespacial (Spain), the Universidad Politéchnica de Madrid (Spain), the Department of Physics and Astronomy of Uppsala University (Sweden), and the Institute of Computer and Network Engineering of the TU Braunschweig (Germany). OSIRIS was financially supported by the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), and Sweden (SNSB) and the ESA Technical Directorate.