[meteorite-list] Cruise Over Ceres in New Video

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Fri, 7 Aug 2015 16:01:46 -0700 (PDT)
Message-ID: <201508072301.t77N1kkT024070_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.php?feature=4677

Cruise Over Ceres in New Video
Jet Propulsion Laboratory
August 6, 2015

Striking 3-D detail highlights a towering mountain, the brightest spots
and other features on dwarf planet Ceres in a new video from NASA's Dawn
mission.

http://www.jpl.nasa.gov/video/details.php?id=1392

A prominent mountain with bright streaks on its steep slopes is especially
fascinating to scientists. The peak's shape has been likened to a cone
or a pyramid. It appears to be about 4 miles (6 kilometers) high, with
respect to the surface around it, according to the latest estimates. This
means the mountain has about the same elevation as Mount McKinley in Denali
National Park, Alaska, the highest point in North America.

"This mountain is among the tallest features we've seen on Ceres to date,"
said Dawn science team member Paul Schenk, a geologist at the Lunar and
Planetary Institute, Houston. "It's unusual that it's not associated with
a crater. Why is it sitting in the middle of nowhere? We don't know yet,
but we may find out with closer observations."

Also puzzling is the famous Occator (oh-KAH-tor) crater, home to Ceres'
brightest spots. A new animation simulates the experience of a close flyover
of this area. The crater takes its name from the Roman agriculture deity
of harrowing, a method of pulverizing and smoothing soil.

In examining the way Occator's bright spots reflect light at different
wavelengths, the Dawn science team has not found evidence that is consistent
with ice. The spots' albedo -? a measure of the amount of light reflected
-? is also lower than predictions for concentrations of ice at the surface.

"The science team is continuing to evaluate the data and discuss theories
about these bright spots at Occator," said Chris Russell, Dawn's principal
investigator at the University of California, Los Angeles. "We are now
comparing the spots with the reflective properties of salt, but we are
still puzzled by their source. We look forward to new, higher-resolution
data from the mission's next orbital phase."

An animation of Ceres' overall geography, also available in 3-D, shows
these features in context. Occator lies in the northern hemisphere, whereas
the tall mountain is farther to the southeast (11 degrees south, 316 degrees
east).

"There are many other features that we are interested in studying further,"
said Dawn science team member David O'Brien, with the Planetary Science
Institute, Tucson, Arizona. "These include a pair of large impact basins
called Urvara and Yalode in the southern hemisphere, which have numerous
cracks extending away from them, and the large impact basin Kerwan, whose
center is just south of the equator."

Ceres is the largest object in the main asteroid belt between Mars and
Jupiter. Thanks to data acquired by Dawn since the spacecraft arrived
in orbit at Ceres, scientists have revised their original estimate of
Ceres' average diameter to 584 miles (940 kilometers). The previous estimate
was 590 miles (950 kilometers).

Dawn will resume its observations of Ceres in mid-August from an altitude
of 900 miles (less than 1,500 kilometers), or three times closer to Ceres
than its previous orbit.

On March 6, 2015, Dawn made history as the first mission to reach a dwarf
planet, and the first to orbit two distinct extraterrestrial targets.
It conducted extensive observations of Vesta in 2011-2012.

Dawn's mission is managed by NASA's Jet Propulsion Laboratory for NASA's
Science Mission Directorate in Washington. Dawn is a project of the directorate's
Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville,
Alabama. UCLA is responsible for overall Dawn mission science. Orbital
ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The
German Aerospace Center, Max Planck Institute for Solar System Research,
Italian Space Agency and Italian National Astrophysical Institute are
international partners on the mission team. For a complete list of mission
participants, visit:

http://dawn.jpl.nasa.gov/mission

More information about Dawn is available at the following sites:

http://dawn.jpl.nasa.gov

http://www.nasa.gov/dawn


Media Contact

Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, CA
818-354-6425
elizabeth.landau at jpl.nasa.gov

2015-260
Received on Fri 07 Aug 2015 07:01:46 PM PDT