Structure and Evolution of Disks Around Brown Dwarfs and Very Low Mass Stars

We propose a program of deep PACS photometry of 50 young brown dwarfs and YSOs at the hydrogenburning limit, 0.08 solar masses. We have selected these from documented BDs in the literature that have been observed to have circumstellar disks based on their 124um SEDs. None of these objects is bright enough to have been detectable with Spitzer beyond 24um. We eliminated objects from our list that are likely to be detected in the largearea Herschel Key Project surveys of starforming regions, and we also eliminated objects whose disks are likely to be below our detection limit of a few mJy at 70um. We expect to be able to detect or obtain important upper limits on the cold disk emission at 70um for all 50 sources, and to obtain useful detections or limits at 160um for at least a third of our objects. We will combine our results with those from Spitzer and groundbased telescopes and then model the SEDs with two different radiative transfer codes existing at the University of Kiel and University of Grenoble. These results will provide the first quantitative assessment of the structure and mass of cold dust around the lowest mass objects that form like stars. Our data and modeling will provide important new constraints to the understanding of disk evolution and planet formation by extending the range of central object masses to virgul 0.01 solar masses. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]