[meteorite-list] Dawn's Ceres Color Map Reveals Surface Diversity

[Ron Baalke]

http://www.jpl.nasa.gov/news/news.php?feature=4548

Dawn's Ceres Color Map Reveals Surface Diversity
Jet Propulsion Laboratory
April 13, 2015

A new color map of dwarf planet Ceres, which NASA's Dawn spacecraft has 
been orbiting since March, reveals the diversity of the surface of this 
planetary body. Differences in morphology and color across the surface 
suggest Ceres was once an active body, Dawn researchers said today at 
the 2015 General Assembly of the European Geosciences Union in Vienna.

"This dwarf planet was not just an inert rock throughout its history. 
It was active, with processes that resulted in different materials in 
different regions. We are beginning to capture that diversity in our color 
images," said Chris Russell, principal investigator for the Dawn mission, 
based at the University of California, Los Angeles.

The Dawn mission made history on March 6 as the first spacecraft to reach 
a dwarf planet, and the first spacecraft to orbit two extraterrestrial 
targets. Previously, Dawn studied giant asteroid Vesta from 2011 to 2012, 
uncovering numerous insights about its geology and history. While Vesta 
is a dry body, Ceres is believed to be 25 percent water ice by mass. By 
comparing Vesta and Ceres, scientists hope to gain a better understanding 
of the formation of the solar system.

Ceres' surface is heavily cratered, as expected, but appears to have fewer 
large craters than scientists anticipated. It also has a pair of very 
bright neighboring spots in its northern hemisphere. More detail will 
emerge after the spacecraft begins its first intensive science phase on 
April 23, from a distance of 8,400 miles (13,500 kilometers) from the 
surface, said Martin Hoffmann, investigator on the Dawn framing camera 
team, based at the Max Planck Institute for Solar System Research, Gottingen, 
Germany.

The visible and infrared mapping spectrometer (VIR), an imaging spectrometer 
that examines Ceres in visible and infrared light, has been examining 
the relative temperatures of features on Ceres' surface. Preliminary examination 
suggests that different bright regions on Ceres' surface behave differently, 
said Federico Tosi, investigator from the VIR instrument team at the Institute 
for Space Astrophysics and Planetology, and the Italian National Institute 
for Astrophysics, Rome.

Based on observations from NASA's Hubble Space Telescope, planetary scientists 
have identified 10 bright regions on Ceres' surface. One pair of bright 
spots, by far the brightest visible marks on Ceres, appears to be located 
in a region that is similar in temperature to its surroundings. But a 
different bright feature corresponds to a region that is cooler than the 
rest of Ceres' surface.

The origins of Ceres' bright spots, which have captivated the attention 
of scientists and the public alike, remain unknown. It appears the brightest 
pair is located in a crater 57 miles (92 kilometers) wide. As Dawn gets 
closer to the surface of Ceres, better-resolution images will become available.

"The bright spots continue to fascinate the science team, but we will 
have to wait until we get closer and are able to resolve them before we 
can determine their source," Russell said.

Both Vesta and Ceres are located in the main asteroid belt between Mars 
and Jupiter. The Dawn spacecraft will continue studying Ceres through 
June 2016.

Dawn's mission is managed by NASA's Jet Propulsion Laboratory, Pasadena, 
California, 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/

For more information about Dawn, visit:

http://dawn.jpl.nasa.gov

Media Contact
Elizabeth Landau
NASA's Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6425
Elizabeth.Landau at jpl.nasa.gov

2015-125