Ron and List,
Thanks as always Ron for posting these articles. I look at the
pictures of the mountain/central complex on the south polar region of
Vesta and can't help but wonder, could that "mountain" actually be a
rebound peak?
Mike in CO
On Oct 12, 2011, at 1:26 PM, Ron Baalke wrote:
http://www.jpl.nasa.gov/news/news.cfm?release=2011-319
NASA's Dawn Science Team Presents Early Science Results
Jet Propulsion Laboratory
October 12, 2011
Scientists with NASA's Dawn mission are sharing with other scientists
and the public their early information about the southern hemisphere
of
the giant asteroid Vesta. The findings were presented today at the
annual meeting of the Geological Society of America in Minneapolis,
Minn.
Dawn, which has been orbiting Vesta since mid-July, has found that the
asteroid's southern hemisphere boasts one of the largest mountains in
the solar system. Other findings show that Vesta's surface, viewed by
Dawn at different wavelengths, has striking diversity in its
composition, particularly around craters. Science findings also
include
an in-depth analysis of a set of equatorial troughs on Vesta and a
closer look at the object's intriguing craters. The surface appears to
be much rougher than most asteroids in the main asteroid belt. In
addition, preliminary dates from a method that uses the number of
craters indicate that areas in the southern hemisphere are as young
as 1
billion to 2 billion years old, much younger than areas in the north.
Scientists do not yet understand how all the features on Vesta's
surface
formed, but they did announce today, after analysis of northern and
southern troughs, that results are consistent with models of fracture
formation due to giant impact.
Since July, the Dawn spacecraft has been spiraling closer and closer
to
Vesta, moving in to get better and better views of the surface. In
early
August, the spacecraft reached an orbital altitude of 1,700 miles
(2,700
kilometers) and mapped most of the sunlit surface, during survey
orbit,
with its framing camera and visible and infrared mapping spectrometer.
That phase was completed in late August, and the spacecraft began
moving
in to what is known as High Altitude Mapping Orbit at about 420 miles
(680 kilometers) above Vesta, which it reached on Sept. 29.
An archive of the live news conference is available for viewing at:
http://www.ustream.tv/nasajpl2 .
The Dawn scientists also shared their findings at the recent European
Planetary Science Congress and the Division of Planetary Sciences
Joint
Meeting 2011 in Nantes, France.
Dawn launched in September 2007 and arrived at Vesta on July 15, 2011.
Following a year at Vesta, the spacecraft will depart in July 2012 for
the dwarf planet Ceres, where it will arrive in 2015.
Dawn's mission to Vesta and Ceres is managed by the Jet Propulsion
Laboratory, Pasadena, Calif., for NASA's Science Mission Directorate
in
Washington. JPL is a division of the California Institute of
Technology
in Pasadena. Dawn is a project of the directorate's Discovery Program,
managed by NASA's Marshall Space Flight Center in Huntsville, Ala.
UCLA
is responsible for overall Dawn mission science. Orbital Sciences
Corp.
in Dulles, Va., designed and built the spacecraft. The German
Aerospace
Center, the Max Planck Institute for Solar System Research, the
Italian
Space Agency and the Italian National Astrophysical Institute are
international partners on the mission team.
For more information about the Dawn mission, visit:
http://www.nasa.gov/dawn and http://dawn.jpl.nasa.gov . To follow the
mission on Twitter, visit: http://www.twitter.com/NASA_Dawn .
Priscilla Vega 818-354-1357
Jet Propulsion Laboratory, Pasadena, Calif.
[email protected]
2011-319
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