KECK OBSERVATORY
Photos released yesterday show multiple images of Davida
Keck telescope renders
details of asteroid
WAIMEA, Hawaii >> Keck Observatory has released photos of the asteroid Davida, the first ground-based images showing the object's irregular shape with hints of surface details.
Previous images showed the 200-mile-diameter object only as a pinpoint of light.
The new images were made Dec. 26 by a team at the Keck observatory. They were made public yesterday following presentation last week at a meeting of the American Astronomical Society in Monterey, Calif., said astronomer Albert Conrad, part of the 10-member team.
Davida was discovered in 1903. With a diameter about as big as the distance from Honolulu to Hilo, it is one of the larger objects in the asteroid belt between Mars and Jupiter.
Seeing details of its surface is the equivalent of seeing a quarter from 11 miles away, a Keck statement said.
Astronomers are not yet sure about those details, Conrad said. The images show patterns of light and dark, but some of the marks are artificial, created by sharpening the images, he said.
The images show objects about 30 miles across, or about the size of San Francisco Bay, the Keck statement said. The team was able to see as much detail as it did because of adaptive optics, which removes the blurring of the Earth's atmosphere from observations.
The team, looking at Davida from its north pole, was able to watch the asteroid rotate through a complete 5.1-hour "day."
An animation showing the rotation can be seen at www2.keck.hawaii.edu/news/asteroid/x_anim.gif.
The observations were made while Davida was near its closest approach to Earth, about 150 million miles away, Conrad said. In comparison, Mars was 34 million miles away during its recent approach to Earth.
The close-up images of Davida are only about the fifth set of images of large asteroids seen by ground-based telescopes since Keck first took close-ups of the asteroid Juno in 2000, Conrad said.
Asteroids are believed to be objects that would have formed a planet when the solar system was young but were prevented from doing so by the massive gravity of Jupiter.
Studies such as the Davida images may show how they have crashed into each other over time, the Keck statement said.
