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LEGACY TEAM WILL USE SPACE INFRARED TELESCOPE FACILITY
TO TRACE FORMATION, EVOLUTION OF PLANETARY SYSTEMS

From Lori Stiles, UA News Services, 520-621-1877)
April 14, 2003

Part 2 of 2

"If you were observing our system from afar, you would see that in
the spectral energy distribution. You'd see a lot of hot and warm
dust inside the orbit of the asteroid belt. You'd see a lot of very
cold dust associated with the Kuiper Belt. And you'd see a gap
created by Jupiter in between. That's exactly the kind of signature
we're looking for," Meyer said. "If we see large gaps in the dust
distribution, that would be a smoking gun, evidence that planets
there could be there, sculpting the dust." 

Meyer and his colleagues have modeled how our solar system might have
looked when it was one million years old, and how it changed through
time, at 100 million years, at one billion years, at 4.5 billion
years. It's like a blueprint in the search for other planetary
systems. 

Their Legacy project may also help settle a current raging debate
about whether or not Jupiter-mass planets form very quickly in gas
disks around young stars.

Recent ground-based observations support the idea that such planets
form as quickly as one million years from the molecular hydrogen in
circumstellar disks.

That conflicts with findings from the European Space Agency's
infrared "ISO" mission, which suggested that molecular hydrogen disks
around stars have long lifetimes, and so could form planets like our
Jupiter over timescales longer than 10 million years.

Using the Infrared Spectrograph on SIRTF, Meyer and his colleagues
will measure the mass of molecular hydrogen in circumstellar disks of
stars in their study.

"If we don't see any gas around stars older than 3 million years,
then perhaps planets like our own Jupiter may have trouble forming,"
Meyer said. "On the other hand, if we see gas-rich disks within 10
million to 20 million years, chances are greater that there may be
more solar systems like our own whether planets form quickly or not."

Members of the 'FEPS' Legacy team include:

*    UA Steward Observatory -- Michael R. Meyer (principal
investigator), Dean Hines, J. Serena Kim, Murray Silverstone, Erick
Young, E. Mamajek, A. Moro-Martin
*    UA Lunar and Planetary Laboratory -- Jonathan I. Lunine, Renu
Malhotra
*    California Institute of Technology -- Lynn Hillenbrand (deputy
principal investigator), John Carpenter, Sebastian Wolf
*    Max Planck Institute, Heidelberg -- Jens Rodmann, Thomas Henning
*    NASA Ames Research Center, Franklin & Marshall -- Dana Backman
(deputy principal investigator)
*    NASA Ames Research Center -- David Hollenbach, Uma Gorti
*    National Optical Astronomy Observatory -- Joan Najita, Steve
Strom
*    Planetary Sciences Institute -- Stuart Weidenschilling
*    SIRTF Science Center -- Pat Morris, Deborah Padgett, John
Stauffer
*    Space Telescope Science Institute --Steve Beckwith, David
Soderblom
*    University of California - Berkeley -- Martin Cohen
*    University of Rochester -- Dan Watson

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