>From: "NASA Jet Propulsion Laboratory" <info@jpl.nasa.gov>
>Reply-To: <info@jpl.nasa.gov>
>To: "Larry Klaes" <ljk4@msn.com>
>Subject: NASA's Spitzer Telescope Sees Signs of Alien Asteroid Belt
>Date: Wed, 20 Apr 2005 11:11:19 -0700
>
>MEDIA RELATIONS OFFICE
>JET PROPULSION LABORATORY
>CALIFORNIA INSTITUTE OF TECHNOLOGY
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>http://www.jpl.nasa.gov
>
>Whitney Clavin (818) 354-4673
>Jet Propulsion Laboratory, Pasadena, Calif.
>
>News Release: 2005-060 April 20, 2005
>
>NASA's Spitzer Telescope Sees Signs of Alien Asteroid Belt
>
>NASA's Spitzer Space Telescope has spotted what may be the dusty
>spray of asteroids banging together in a belt that orbits a star
>like our Sun. The discovery offers astronomers a rare glimpse at
>a distant star system that resembles our home, and may represent
>a significant step toward learning if and where other Earths
>form.
>
>"Asteroids are the leftover building blocks of rocky planets like
>Earth," said Dr. Charles Beichman of the California Institute of
>Technology, Pasadena, Calif. Beichman is lead author of a paper
>that will appear in the Astrophysical Journal. "We can't directly
>see other terrestrial planets, but now we can study their dusty
>fossils."
>
>Asteroid belts are the junkyards of planetary systems. They are
>littered with the rocky scraps of failed planets, which
>occasionally crash into each other, kicking up plumes of dust. In
>our own solar system, asteroids have collided with Earth, the
>moon and other planets.
>
>If confirmed, the new asteroid belt would be the first detected
>around a star about the same age and size as our Sun. The star,
>called HD69830, is located 41 light-years away from Earth. There
>are two other known distant asteroid belts, but they circle
>younger, more massive stars.
>
>While this new belt is the closest known match to our own, it is
>not a perfect twin. It is thicker than our asteroid belt, with 25
>times as much material. If our solar system had a belt this
>dense, its dust would light up the night skies as a brilliant
>band.
>
>The alien belt is also much closer to its star. Our asteroid belt
>lies between the orbits of Mars and Jupiter, whereas this one is
>located inside an orbit equivalent to that of Venus.
>
>Yet, the two belts may have one important trait in common. In our
>solar system, Jupiter acts as an outer wall to the asteroid belt,
>shepherding its debris into a series of bands. Similarly, an
>unseen planet the size of Saturn or smaller may be marshalling
>this star's rubble.
>
>One of NASA's future planet-hunting missions, SIM PlanetQuest,
>may ultimately identify such a planet orbiting HD 69830. The
>mission, which will detect planets as small as a few Earth
>masses, is scheduled to launch in 2011.
>
>Beichman and colleagues used Spitzer's infrared spectrograph to
>observe 85 Sun-like stars. Only HD 69830 was found to possibly
>host an asteroid belt. They did not see the asteroids themselves,
>but detected a thick disk of warm dust confined to the inner
>portion of the star system. The dust most likely came from an
>asteroid belt in which dusty smash-ups occur relatively
>frequently, about every 1,000 years.
>
>"Because this belt has more asteroids than ours, collisions are
>larger and more frequent, which is why Spitzer could detect the
>belt," said Dr. George Rieke, University of Arizona, Tucson, co-
>author of the paper. "Our present-day solar system is a quieter
>place, with impacts of the scale that killed the dinosaurs
>occurring only every 100 million years or so."
>
>To confirm that the dust detected by Spitzer is indeed ground-up
>asteroids, a second less-likely theory will have to be ruled out.
>According to the astronomers, it is possible a giant comet,
>almost as big as Pluto, got knocked into the inner solar system
>and is slowly boiling away, leaving a trail of dust. This
>hypothesis came about when the astronomers discovered the dust
>around the star consists of small silicate crystals like those
>found in comet Hale-Bopp. One of these crystals is the bright
>green-colored gem called forsterite.
>
>"The 'super comet' theory is more of a long shot," Beichman said,
>"but we'll know soon enough." Future observations of the star
>using Spitzer and ground-based telescopes are expected to
>conclude whether asteroids or comets are the source of the dust.
>
>Other authors of this study include G. Bryden, T. Gautier, K.
>Stapelfeldt and M. Werner of NASA's Jet Propulsion Laboratory,
>Pasadena, Calif.; and K. Misselt, J. Stansberry and D. Trilling
>of the University of Arizona.
>
>The Jet Propulsion Laboratory manages the Spitzer Space Telescope
>mission for NASA's Science Mission Directorate, Washington.
>Science operations are conducted at the Spitzer Science Center,
>at the California Institute of Technology in Pasadena. Caltech
>manages JPL for NASA. Spitzer's infrared spectrograph was built
>by Cornell University, Ithaca, N.Y. Its development was led by
>Dr. Jim Houck of Cornell.
>
>For artist's concepts and more information, visit:
>www.spitzer.caltech.edu/spitzer .
>
> -end-
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