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D. E. Trilling, G. H. Rieke, K. Y. L. Su, J. A. Stansberry (UA), C. A. Beichman, G. Bryden, K. R. Stapelfeldt, M. W. Werner (JPL)
In the past year, the Spitzer Space Telescope has returned thermal infrared (24, 70, 160 micron) images of unprecedented sensitivity, allowing searches for debris disks around stars. We will provide a brief overview of results from several ongoing Spitzer debris disk programs, highlighting results from three programs. First, we learn from our survey of more than 250 A stars that there is substantial variety in the intrinsic properties of debris disks, dating from their protoplanetary stages. We further argue that much of the dust we see today is generated from episodic planetesimal collisions. Second, our detailed study of Vega allows us to map a large debris disk and constrain particle size and dust dynamics. We find that very small dust grains are being blown out from the inner part of the Vega system, suggesting a recent dust-producing collision. Third, from a preliminary survey of nearby Sun-like stars, we find that the prevalence of debris disks around extrasolar planet-bearing stars is relatively high, implying the presence of dust-producing bodies (asteroids, comets) in those systems. The overall picture of planetary system formation from planetesimals is supported by all of these results. However, the observational signatures of dust disks (and consequently the late-stage evolution of those disks) may be alluding not to steady-state conditions but to large, individual, dust-producing events. This work is based on observations made with the Spitzer Space Telescope, operated by JPL/Caltech under NASA contract 1407. Support for this work was provided by NASA through contract number 960785 issued by JPL/Caltech.
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Bulletin of the American Astronomical Society, 36 #4
© 2004. The American Astronomical Soceity.