Abstract

We consider a representative sample of more than thirty debris disks around AFGKM stars well resolved in various Herschel Space Observatory programs, which is probably the largest set of resolved disks ever analyzed. For each target, the disk radius is inferred from the resolved PACS images, and the spectral energy distribution is modeled with two different methods to determine the amount of dust, its temperature, and the size distribution. The results are used to investigate how various disk parameters (dust fractional luminosity, disk radius, typical dust grain size, dust opacity) depend on the stellar parameters (spectral type, luminosity, age, and metallicity). For instance, we find no significant trend of disk radii with the stellar luminosity. The dust temperature systematically increases towards earlier spectral types, yet the ratio of the dust temperature to the blackbody temperature at the disk radius decreases with the stellar luminosity. We find a clear trend of typical sizes increasing towards more luminous stars, with a larger scatter towards higher stellar luminosities. Possible explanations for these and other findings are proposed and their implications are discussed.

Presentation

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