Rosetta’s comet takes shape
In current images obtained by OSIRIS, Rosetta’s scientific imaging system, the nucleus of 67P/Churyumov-Gerasimenko covers a good four pixels.
July 03, 2014
Almost there! ESA’s spacecraft Rosetta eases closer and closer to comet 67P/Churyumov-Gerasimenko and has now reached a distance comparable to the small stretch of space that separates weather satellites in geo-stationary orbit from Earth. In new images taken by OSIRIS, Rosetta’s onboard scientific imaging system, the comet’s nucleus is beginning to cover several pixels. The resolved images now give scientists a first hunch of its shape.
“After a long, long journey it feels like we have now entered into 67P’s direct neighborhood. We have only about 40 000 kilometers to go”, says OSIRIS Principal Investigator Holger Sierks from the Max Planck Institute for Solar System Research (MPS) in Germany. In the OSIRIS images produced within the last days, 67P corresponds to a good two by two pixels.
“If you look closely, the comet appears a bit fuzzy and seems to cover a larger area”, Sierks describes the recent images. This is, however, not evidence of a visible dust coma surrounding the nucleus, but due to physical effects of an optical imaging system. Once Rosetta gets closer to the comet and OSIRIS produces high-resolution images, these effects will be negligible. Within the next two weeks, 67P’s image will grow to a size of 20 by 20 pixels.
While the comet’s activity is currently too low as to produce a visible coma, the data does point to a slight increase in dust production. “It is, however, still too early to tell, whether this is only a short event as earlier this year or foreshadow of a continuous increase”, says Sierks.
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.