Feasibility of spatially resolving an unperturbed disk (top) and of detecting a gap induced by a planet with a planet-to-star mass ratio of η = 0.001 (bottom) depending on the disk mass, the host star, the disk size, and ALMA configuration. The disks are made up of large dust grains. The exposure time is two hours at a wavelength of 430 μm. The simulations for a combination of a total disk mass of M = 2.67 × 10^-2 M_⊙ and a scaling factor k < 10 were not calculated. For the scaling factor k see Fig. 5, for the resulting angular resolution depending on wavelength and ALMA configuration see Fig. 3. The scale of one pixel is 0.00064″×k.