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A. J. Weinberger (DTM/Carnegie Institution of Washington)
We are far from having a complete disk census for main sequence stars. All of the disks known today are inferred from excess infrared emission, characterized by the fraction of the star's luminosity which is re-radiated in the mid-to-far-infrared (f). The IRAS survey provides the most sensitive all-sky catalog of infrared emission, including over 100 stars with excess. The IRAS Faint Source Catalog, complete (SNR~5) to a flux density limit of ~0.2 Jy at 12 and 25\micron, had insufficient sensitivity to probe fully for disks. For a fixed number of small dust grains, the more luminous the central star, the brighter a disk will be in the infrared. So, our disk census is most complete for the luminous A-type stars. While these are enormously interesting for their tantalizing hints of dynamically induced structure, the quest for older, optically thin (debris) disks around lower mass stars continues. Planetary systems known from radial velocity surveys are all around approximately solar-mass stars. We need to connect these mature systems with their progenitor disks.
I review the limits of current surveys for debris disks around stars of different luminosities in nearby young stellar associations and clusters. I highlight results from the TW Hydrae association. I also compare some detailed studies of young, nearby debris disks around the A type stars HD 141569A, HR 4796A, and Beta Pictoris.
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Bulletin of the American Astronomical Society, 35 #3
© 2003. The American Astronomical Soceity.