[meteorite-list] New NASA Dawn Visuals Show Vesta's 'Color Palette'

[Ron Baalke]

http://www.jpl.nasa.gov/news/news.cfm?release=2011-375&cid=release_2011-375&msource=2011375&tr=y&auid=9960738

New NASA Dawn Visuals Show Vesta's 'Color Palette'
Jet Propulsion Laboratory
December 5, 2011

Vesta appears in a splendid rainbow-colored palette in new images obtained by NASA's Dawn spacecraft. 
The colors, assigned by scientists to show different rock or mineral types, reveal Vesta to be a world 
of many varied, well-separated layers and ingredients. Vesta is unique among asteroids visited by 
spacecraft to date in having such wide variation, supporting the notion that it is transitional 
between the terrestrial planets -- like Earth, Mercury, Mars and Venus -- and its asteroid siblings.

In images from Dawn's framing camera, the colors reveal differences in the rock composition associated 
with material ejected by impacts and geologic processes, such as slumping, that have modified the asteroid's 
surface. Images from the visible and infrared mapping spectrometer reveal that the surface materials 
contain the iron-bearing mineral pyroxene and are a mixture of rapidly cooled surface rocks and a deeper 
layer that cooled more slowly. The relative amounts of the different materials mimic the topographic 
variations derived from stereo camera images, indicating a layered structure that has been excavated by 
impacts. The rugged surface of Vesta is prone to slumping of debris on steep slopes.

Dawn scientists presented the new images at the American Geophysical Union meeting in San Francisco on Monday, 
Dec. 5. The panelists included Vishnu Reddy, framing camera team associate, Max Planck Institute for Solar 
System Research, Katlenburg-Lindau, Germany; Eleonora Ammannito, visible and infrared spectrometer team 
associate, Italian Space Agency, Rome; and David Williams, Dawn participating scientist, Arizona State 
University, Tucson.

"Vesta's iron core makes it special and more like terrestrial planets than a garden-variety asteroid,"` 
said Carol Raymond, Dawn's deputy principal investigator at NASA's Jet Propulsion Laboratory, Pasadena, 
Calif. "The distinct compositional variation and layering that we see at Vesta appear to derive from 
internal melting of the body shortly after formation, which separated Vesta into crust, mantle and core."
The presentation also included a new movie, created by David O'Brien of the Planetary Science Institute, 
Tucson, Ariz., that takes viewers on a spin around a hill on Vesta that appears to be made of a distinctly 
darker material than the rest of the crust.

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 JPL 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.

More information about the Dawn mission is online at: 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.
Priscilla.R.Vega at jpl.nasa.gov

2011-375