SIMBAD references

We study dust accumulation by photophoresis in optically thin gas disks. Using formulae for the photophoretic force that are applicable for the free molecular regime and for the slip-flow regime, we calculate dust accumulation distances as a function of particle size. It is found that photophoresis pushes particles (smaller than 10 cm) outward. For a Sun-like star, these particles are transported to 0.1-100 AU, depending on their size, and form an inner disk. Radiation pressure pushes small particles (≲1 mm) out further to form an extended outer disk. Consequently, an inner hole opens inside ∼0.1 AU. The radius of the inner hole is determined by the condition that the mean free path of the gas molecules equal the maximum size of the particles that photophoresis effectively works on (100 µm-10 cm, depending on the dust properties). The dust disk structure formed by photophoresis can be distinguished from the structure of model gas-free dust disks, because the particle sizes in the outer disk are larger, and the inner hole radius depends on the gas density.