Comets as a Source of the Dust in the ß Pictoris Disk

Abstract

The infrared continuum and the 10 μm spectral energy distribution of the dust in the disk of ß Pictoris may be derived by assuming that the dust is continually replenished by comets orbiting close to the star. The basic, initial dust shed by the comets is taken to be the fluffy aggregates of interstellar silicate core-organic refractory mantle dust grains whose size distribution is like that observed for Comet Halley. The primary heating provided by the organic refractory mantle absorption of the stellar radiation, is sufficient for some of the particles to crystallize the initially amorphous silicates. The dust grains are then distributed in the disk by radiation pressure. In steady state the disk then consists of a mixture of crystalline silicate aggregates and aggregates of amorphous silicate core-organic refractory mantle particles with variable ratios of organic refractory to silicate mass. The temperature distribution of a radial distribution of such particles provides an excellent match to the silicate 10 μm (plus 11.2 μn) spectral emission as well as the excess continuum flux from the disk.KeywordsSpectral Energy DistributionInterstellar DustDust MassComet DustAmorphous SilicateThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.