Assigned ID: 1072 ----- Attempting Submission 1 (Sat Feb 25 00:55:13 GMT 2012) ----- Debris disks are circumstellar dust clouds that trace extrasolar analogs of our solar system's Kuiper Belt. Over the years HST users have sought to image dozens of debris disks around stars selected to have far-infrared excess. While many notable imaging detections have been achieved, the vast majority of the targeted disks have gone undetected in scattered light. These non-detections are generally not interpreted or published by the original observing teams. A major opportunity to do science with these non-detections is now opening thanks to the Herschel Space Observatory, which has resolved the sizes of these disks for the first time. In a pilot study of HD 48682, a model fit to the resolved Herschel image and disk excess spectrum was used to make quantitative predictions of the brightness and radial location of scattered light from the star's debris disk. The HST archival image of the system is sufficiently sensitive to require the debris dust albedo to be <10%, which rules out an icy composition for the grains. We propose to perform a similar analysis on 24 additional debris disks resolved with Herschel and undetected in HST images. We will derive quantitative detection upper limits from the PSF-subtracted HST images and interpret them in the context of the Herschel and Spitzer data. Our project will more than double the number of debris disks with quantitative albedo constraints, and thus help to clarify the nature of dusty material in extrasolar planetary systems. ISM AND CIRCUMSTELLAR MATTER 12 Medium false 0.0 0.0 false false false false SUPPORTED