A model grid for the reflected light from transition disks

The dust in protoplanetary disks is an important ingredient in planet formation and can be investigated with model simulations and quantitative imaging polarimetry of the scattered stellar light. This study explores circumstellar disks with calculations for the intensity and polarization of the reflected light. The photon scattering and absorption by the disk are calculated with a Monte Carlo method for a grid of simple, rotationally symmetric models approximated at each point by a plane-parallel dusty atmosphere. The results of our simple disk models reproduce well the measurements for the intensity $I/I_{\star}$, azimuthal polarization $Q_{\varphi}/I_{\star}$, and fractional polarization $p_{\varphi}$ reported for well-observed transition disks. They describe the dependencies of the scattered radiation on the disk geometry and the dust scattering parameters in detail. Particularly strong constraints on disk properties can be obtained from certain diagnostic quantities. Therefore, they can be used as a diagnostic tool for the analysis of quantitative measurements, specifically in constraining or even determining the scattering properties of the dust particles in disks. Collecting and comparing such information for many systems is required to understand the nature of the scattering dust in planet-forming disks.