Shadows in the Sky - What They May Tell Us
Bringfried Stecklum

Both the high optical depth close to the mid-plane of a circumstellar disk and the light scattering by dust in the surrounding medium lead an equatorial shadow which can be confused with a large-scale extinction lane. Depending on the distribution of the scattering dust, the disk shadow can be much larger in size than the disk and strongly distorted as well. Nevertheless, the analysis of the shadow appearance and its possible change over time provides information on the disk which is hard to get otherwise. By discussing the disk shadows of RY Tau and LkHA 208, these propositions will be illustrated.