Vesta is coming into view of the Dawn spacecraft and this video shows surface details just beginning to resolve as Dawn gets closer to its first destination. The images were obtained on June 1st and show, for the first time, a dark feature with a diameter of approximately 100 kilometers near the asteroid’s equator. “We won’t know what this dark spot is for a few weeks, when we have come a bit closer to the asteroid” said Dr. Vishnu Reddy and Dr. Lucille Le Corre from Max Planck Institute for Solar System Research (MPS) in Germany. Both scientists analyzed the data received from the Dawn framing camera.
Older images taken by NASA’s Hubble Space Telescope had revealed a similar structure. Visible are Vesta’s jagged shape (created by repeated impacts) and variations in surface brightness. Vesta’s south pole is to the lower right at about the 5 o’clock position.
The video shows 20 frames, looped five times, that span a 30-minute period. During that time, Vesta rotates about 30 degrees. The images included here are used by navigators to fine-tune Dawn’s trajectory during its approach to Vesta, with arrival expected on July 16, 2011.
Dawn’s framing camera obtaied the images from a distance of about 483,000 kilometers (300,000 miles).
Vesta is 530 kilometers (330 miles) in diameter and the second most massive object in the asteroid belt. It is also the only large asteroid with a basaltic surface formed due to volcanic processes early in the solar system’s history. Vesta is considered a protoplanet because it is a large body that almost formed into a planet.