Update from Dawn’s Exploration of Vesta

Posted: September 29, 2011 - 08:20 , by Ian Nicklin

Embedded video from NASA Jet Propulsion Laboratory California Institute of Technology

The Dawn mission is providing us with some of the most detailed images of any asteroidal body to date. Before Dawn’s arrival at Vesta the best images available were fuzzy, computer-enhanced shots taken by the Hubble telescope. This video flyby of Vesta’s surface is unprecedented and it will only get better! Currently Dawn is orbiting at 2,700 kilometers above Vesta’s surface. At this altitude Dawn is able to create an accurate map of the surface, plot large features and determine Vesta’s rotational axis. In October Dawn will spiral into a lower orbit where more details will be seen. All the information gathered by Dawn – mineralogical composition of the surface, gravity measurements, etc. – will provide many insights into the processes of planetary formation, the same processes which likely formed the Earth.

Already Dawn has rewritten the book on Vesta. The prominent feature at the southern pole could be made out in the Hubble images. But now we see that this feature is actually a mountain, 15 kilometers high, making it one of the highest peaks in the solar system. It sits in the middle of an enormous crater, caused by a collision between Vesta and another asteroid long ago. This crater is hundreds of kilometers across with cliff walls also several kilometers high. The impact which formed this crater most likely also formed the deep troughs that run around the equator of Vesta.

Vesta was first seen by the astronomer Heinrich Wilhelm Olbers, on the 29th of March, 1807. He named it after the Roman goddess Vesta, the goddess of hearth and home. In honour of Olbers’ sighting other features on Vesta will also be named after Roman goddesses or famous Roman women. A 500 meter diameter crater has already been named Claudia. This crater was used to mark the prime meridian for a map of Vesta’s surface. Over the next year Dawn will undoubtedly yield more spectacular surprises but its mission will not end there. Sometime in 2012 it will leave Vesta and head for Ceres, the largest asteroid in our solar system and a world entirely different from Vesta.

Want to learn more about Vesta? You can see the world’s most comprehensive collection of meteorites thought to be from Vesta on temporary display in the Teck Suite of Galleries: Earth’s Treasures.