[meteorite-list] Surface Impressions of Rosetta's Comet

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 24 Jul 2014 11:53:29 -0700 (PDT)
Message-ID: <201407241853.s6OIrTfM010098_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.php?release=2014-243

Surface impressions of Rosetta's comet
Jet Propulsion Laboratory
July 24, 2014

Surface structures are becoming visible in new images of comet
67P/Churyumov-Gerasimenko taken by the scientific imaging system OSIRIS
onboard the European Space Agency's Rosetta spacecraft. The resolution
of these images is now 330 feet (100 meters) per pixel. One of the most
striking features is currently found in the comet's neck region. This
part of 67P seems to be brighter than the rest of the nucleus.

As earlier images had already shown, 67P may consist of two parts: a
smaller head connected to a larger body. The connecting region, the
neck, is proving to be especially intriguing. "The only thing we know
for sure at this point is that this neck region appears brighter
compared to the head and body of the nucleus," says OSIRIS Principal
Investigator Holger Sierks from the Max Planck Institute for Solar
System Research in Germany. This collar-like appearance could be caused
by differences in material or grain size, or could be a topographical
effect.

Even though the images taken from a distance of 3,400 miles (5,500
kilometers) are still not highly resolved, the scientists are remotely
reminded of comet 103P/Hartley, which was visited in a flyby by NASA's
EPOXI mission in 2010. While Hartley's ends show a rather rough surface,
its middle is much smoother. Scientists believe this waist to be a
gravitational low: since it contains the body's center of mass, emitted
material that cannot leave the comet's gravitational field is most
likely to be re-deposited there.

Whether this also holds true for 67P's neck region is still unclear.
Another explanation for the high reflectivity could be a different
surface composition. In coming weeks, the OSIRIS team hopes to analyze
the spectral data of this region obtained with the help of the imaging
system's filters. These can select several wavelength regions from the
reflected light, allowing scientists to identify the characteristic
fingerprints of certain materials and compositional features.

At the same time, the team is currently modeling the comet's
three-dimensional shape from the camera data. Such a model can help to
get a better impression of the body's shape.

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.

Rosetta's Philae lander is provided by a consortium led by the German
Aerospace Center, Cologne; Max Planck Institute for Solar System
Research, Gottingen; French National Space Agency, Paris; and the
Italian Space Agency, Rome. The Jet Propulsion Laboratory, a division of
the California Institute of Technology, Pasadena, manages the U.S.
participation in the Rosetta mission for NASA's Science Mission
Directorate in Washington. Rosetta carries three NASA instruments in its
21-instrument payload.

For more information on the U.S. instruments aboard Rosetta, visit:

http://rosetta.jpl.nasa.gov

More information about Rosetta is available at:

http://www.esa.int/rosetta

Preston Dyches
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-7013
preston.dyches at jpl.nasa.gov

Dwayne Brown
NASA Headquarters
202-358-1726
dwayne.c.brown at nasa.gov

Markus Bauer European Space Agency, Noordwijk, Netherlands
011-31-71-565-6799
markus.bauer at esa.int

Birgit Krummheuer
Max Planck Institute for Solar System Research
011-49-551-384-979-462
krummheuer at mps.mpg.de

2014-243
Received on Thu 24 Jul 2014 02:53:29 PM PDT