(Sen) - A new 3D model of the asteroid Vesta that also reveals its topography has been created from data captured by NASA's Dawn spacecraft which is still in orbit around the small rocky world.
The animation begins overlooking Vesta's north pole and gradually moves southward. The colours chosen show differences in the surface composition and a detailed view of the material properties of the asteroid. The green colour shows the abundance of iron. Vesta has an iron core with a diameter of around 220 kilometres and is believed to have formed in the same way as the other inner rocky planets.
Visible on the animation are the "snowman" craters Marcia, Calpurnia and Minucia just north of the Vestan equator. Next you can see a band of equatorial troughs and Vesta's heavily cratered surface. As the viewing angle moves towards the southern pole, the large central complex protrudes from the massive Rheasilvia impact basin. The Rheasilvia impact basin has a strong greenish appearance signifying a region abundant in iron.
The 3D model was built from images taken in September and October 2011 by Dawn's framing camera at an average distance to the surface of 420 miles (680 kilometers). The images have an average resolution of about 210 feet (65 meters) per pixel. Further images are to be taken of Vesta's northern hemisphere to enhance the map.
The colour composite mosaic was prepared by the German Aerospace Center. The animation and the topographic model were made by the Planetary Science Institute.
Launched in 2007, Dawn's mission is to study Vesta and the dwarf planet Ceres with the aim of improving our understanding of the evolution of the early Solar System. Vesta was chosen as an example of a rocky world in the inner Solar System whilst Ceres was chosen as an example of an icy body in the outer Solar System.
Dawn reached Vesta in July 2011 and scientists have been studying the data captured, including a geological map of the asteroid which reveals that Vesta has many planet-like properties.
Vesta measures about 578 by 560 by 458 kilometers (359 by 348 by 285 miles).
Dawn is due to depart Vesta on August 26, as it heads off to study its next target, the dwarf planet Ceres.
Ceres was chosen as a very different world to rocky Vesta as it formed much further away from the Sun. Ceres appears to have similarities to the large icy moons of the outer Solar System.
Dawn will arrive at Ceres in 2015.
The Dawn mission is managed by NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology.