[meteorite-list] Dawn Team Shares New Maps and Insights about Ceres

[Ron Baalke]

http://www.jpl.nasa.gov/news/news.php?feature=4725

Dawn Team Shares New Maps and Insights about Ceres
Jet Propulsion Laboratory
September 30, 2015

[Image]
This map-projected view of Ceres was created from images taken by NASA's 
Dawn spacecraft during its high-altitude mapping orbit, in August and 
September, 2015. Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Mysteries and insights about Ceres are being discussed this week at the 
European Planetary Science Conference in Nantes, France. NASA's Dawn spacecraft 
is providing scientists with tantalizing views and other data about the 
intriguing dwarf planet that they continue to analyze.

"Ceres continues to amaze, yet puzzle us, as we examine our multitude 
of images, spectra and now energetic particle bursts," said Chris Russell, 
Dawn principal investigator at the University of California, Los Angeles.

A new color-coded topographic map shows more than a dozen recently approved 
names for features on Ceres, all eponymous for agricultural spirits, deities 
and festivals from cultures around the world. These include Jaja, after 
the Abkhazian harvest goddess, and Ernutet, after the cobra-headed Egyptian 
harvest goddess. A 12-mile (20-kilometer) diameter mountain near Ceres' 
north pole is now called Ysolo Mons, for an Albanian festival that marks 
the first day of the eggplant harvest.

[Image]
Another new Ceres map, in false color, enhances compositional differences 
present on the surface. The variations are more subtle than on Vesta, 
Dawn's previous port of call. Color-coded topographic images of Occator 
(oh-KAH-tor) crater, home of Ceres' brightest spots, and a puzzling, cone-shaped 
4-mile-high (6-kilometer-high) mountain, are also available. Scientists 
are still trying to identify processes that could produce these and other 
unique Cerean phenomena.

"The irregular shapes of craters on Ceres are especially interesting, 
resembling craters we see on Saturn's icy moon Rhea," said Carol Raymond, 
Dawn's deputy principal investigator based at NASA's Jet Propulsion Laboratory, 
Pasadena, California. "They are very different from the bowl-shaped craters 
on Vesta."

A surprising bonus observation came from Dawn's gamma ray and neutron 
spectrometer. The instrument detected three bursts of energetic electrons 
that may result from the interaction between Ceres and radiation from 
the sun. The observation isn't yet fully understood, but may be important 
in forming a complete picture of Ceres.

"This is a very unexpected observation for which we are now testing hypotheses," 
Russell said.

Dawn is currently orbiting Ceres at an altitude of 915 miles (1,470 kilometers), 
and the spacecraft will image the entire surface of the dwarf planet up 
to six times in this phase of the mission. Each imaging cycle takes 11 
days.

Starting in October and continuing into December, Dawn will descend to 
its lowest and final orbit, an altitude of 230 miles (375 kilometers). 
The spacecraft will continue imaging Ceres and taking other  data at higher 
resolutions than ever before at this last orbit. It will remain operational 
at least through mid-2016.

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

Dawn's mission is managed by JPL 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, the Italian Space 
Agency and the 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

Updated on Sept. 30th at 1 p.m. PDT with corrected height of the cone-shaped 
mountain.


Media Contact

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

2015-305