[meteorite-list] High-Resolution Images of Asteroid (511) Davida

From: Tom aka James Knudson <knudson911_at_meteoritecentral.com>
Date: Thu Apr 22 10:29:51 2004
Message-ID: <001101c373c9$fb2da840$8fd143d8_at_malcolm>

Hey list, This asteroid looks like it is oriented, complete with a full
roll-over lip !!!!!
Thanks, Tom
Peregrineflier <><
The proudest member of the IMCA 6168
----- Original Message -----
From: Ron Baalke <baalke_at_zagami.jpl.nasa.gov>
To: Meteorite Mailing List <meteorite-list_at_meteoritecentral.com>
Sent: Friday, September 05, 2003 9:10 AM
Subject: [meteorite-list] High-Resolution Images of Asteroid (511) Davida


>
> http://www2.keck.hawaii.edu/news/asteroid.html
>
> High-Resolution Images of Asteroid (511) Davida
> W.M. Keck Observatory
> September 4, 2003
>
> Davida Image
> Davida Asteroid Rotation Animation
>
> Image Credit: W.M. Keck Observatory
> A sequence of images of asteroid (511)
> Davida, spanning slightly more than one
> hour, as it rotates on Dec. 26, 2002. In this
> view, the asteroid is seen from above its
> north pole, as it spins counter-clockwise,
> left to right. The features on the edges,
> such as the flat facets, show that the
> asteroid has rotated about one-quarter
> turn.
>
>
>
> MONTEREY, Calif. -- A team of scientists from the W.M. Keck Observatory
and
> several other research institutions have made the first full-rotational,
> ground-based observations of asteroid (511) Davida, a large, main-belt
> asteroid that measures 320 km (200 miles) in diameter. These observations
> are among the first high-resolution, ground-based pictures of large
> asteroids, made possible only through the use of adaptive optics on large
> telescopes. This research will help improve understanding of how asteroids
> were formed and provide information about their compositions and
structures.
> Because the asteroids were formed and shaped by collisions, a process that
> also affected the Earth, Moon, and planets, these studies will also help
> astronomers understand the history and evolution of the solar system.
>
> " Asteroid Davida was discovered 100 years ago, but this is the first time
> anyone has been able to see this level of detail on this object," said Dr.
> Al Conrad, scientist at the W.M. Keck Observatory. "With adaptive optics,
> we're finally able to transform asteroids like Davida from a single, faint
> point-source into an object of true geological study."
>
> Ground-based observations of large, main-belt asteroids are made possible
> only through a powerful astronomical technique called adaptive optics,
which
> removes the blurring caused by Earth's atmosphere. Without adaptive
optics,
> critical surface information and details about the asteroid's shape are
> lost. The techniques used at the W.M. Keck Observatory allow astronomers
to
> measure the distortion of light caused by the atmosphere and rapidly make
> corrections, restoring the light to near-perfect quality. Such corrections
> are most easily made to infrared light. In many cases, infrared
observations
> made with Keck adaptive optics are better than those obtained with
> space-based telescopes.
>
> The observations of asteroid (511) Davida were made with the 10-meter
> (400-inch) Keck II telescope on December 26, 2002. Images were taken over
a
> full rotation period of about 5.1 hours, just a few days before its
closest
> approach to Earth. At that time, Davida's angular diameter was less than
> one-ten-thousandth of a degree, about the size of a quarter as seen from a
> distance of 18 kilometers (11 miles). The high angular resolution allowed
> astronomers to see surface details as small as 46 kilometers (30 miles),
> about the size of the San Francisco Bay area. The next time Davida comes
> this close to Earth will be in the year 2030.
>
> At the time of the observations, Davida's north pole faced Earth. While
> scientists could see the asteroid spinning, only the northern hemisphere
was
> visible. Yet the profile of the asteroid is far from circular: At least
two
> flat facets can be seen on its surface. Although scientists knew
previously
> from light variations that Davida must have an oblong shape, details of
that
> shape were not available until now. Initial evaluation of the images
reveal
> some dark features, and scientists are still working to understand to what
> extent these are surface markings, topographical features, or artifacts of
> the image processing.
>
> " Adaptive optics on large telescopes is allowing us to make detailed
> studies from the ground that were previously impossible or prohibitively
> expensive," said Dr. William Merline, principal scientist with the
Southwest
> Research Institute, and a participant in this research. "We can now make
> observations that once required either the scarce resources of space
> telescopes or spacecraft missions to asteroids. While these space
telescopes
> and space missions are still needed for complete study of the asteroids,
> ground-based observations such as these will help tremendously in planning
> the mission observations and focusing the resources where they will be
most
> effective."
>
> Asteroids are the collection of rocky objects orbiting between Mars and
> Jupiter. They were likely prevented from forming into a planet, partly due
> to Jupiter's massive gravitational influence.
>
> " Although the asteroids began their lives colliding gently, in a way that
> would lead them eventually to form a planet, Jupiter's gravity eventually
> stirred up their orbits, and they began to collide at higher speeds,"
added
> participant Dr. Christophe Dumas, planetary astronomer with the Jet
> Propulsion Laboratory. "These collisions tended to cause them to break up
> rather than gently stick together. The resulting fragments, numbering in
the
> hundreds of thousands, are the asteroids we see today. They collide with
> each other and have impacted the Earth, Moon, and planets over time. One
> need only look at the scarred surface of our Moon to see the cumulative
> result. Study of the asteroid's shape, size, and surface features helps us
> understand how these collisions operate and thus how our planet was, and
> still is, being affected by these impacts."
>
> Observations of the shapes of asteroids, such as those released today, can
> tell us about the types and severity of impacts that occurred, and
possibly
> also give clues into the overall structure of an asteroid --- for example,
> whether it may be solid rock, or a jumble of smaller rocks. Surface
features
> can reveal a history of large impacts or variations in the composition
that
> should, in turn, further help us understand the asteroid's history.
>
> Asteroid (511) Davida was discovered by R. S. Dugan in 1903 in Heidelberg,
> Germany. The (511) in Davida's name means it was the 511th asteroid to be
> discovered and included in the list of asteroids maintained by the
> International Astronomical Union.
>
> Team members responsible for the observations are Al Conrad, David Le
> Mignant, Randy Campbell, Fred Chaffee, Robert Goodrich, Shui Kwok of the
> W.M. Keck Observatory; Christophe Dumas, Jet Propulsion Laboratory;
William
> Merline, Southwest Research Institute; Heidi Hammel, Space Science
> Institute; and Thierry Fusco, Onera, France.
>
> The W.M. Keck Observatory is operated by the California Association for
> Research in Astronomy, a scientific partnership of the California
Institute
> of Technology, the University of California, and the National Aeronautics
> and Space Administration.
>
> # # #
>
> Dr. William J. Merline, Southwest Research Institute, Boulder, CO;
303-546-9670
> Dr. Christophe Dumas, Jet Propulsion Laboratory, Pasadena, CA;
818-393-5327
> Dr. Albert R. Conrad, W.M. Keck Observatory, Kamuela, HI; 808-881-3812
>
>
> Media Contact:
>
> Laura K. Kraft
> W.M. Keck Observatory
> 65-1120 Mamalahoa Hwy.
> Kamuela, HI96743
> (808) 885-7887
> lkraft_at_keck.hawaii.edu
>
>
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>
Received on Fri 05 Sep 2003 12:23:01 PM PDT