NASA scientists presented a mosaic image of Vesta’s southern hemisphere, showing different rock or mineral types, created from images obtained by the Dawn spacecraft, stated in a press release from the Dawn mission.
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.
The mosaic was assembled using images obtained during approach of the spacecraft to Vesta.
In images from Dawn’s framing camera, the colors reveal differences in the rock composition associated with material ejected by impacts and geologic processes.
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.
“Vesta’s iron core makes it special and more like terrestrial planets than a garden-variety asteroid. 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,” said Carol Raymond, Dawn’s deputy principal investigator at NASA’s Jet Propulsion Laboratory.