Optical depth profiles of both disks derived from Eq. (5). The solid curves show the optical depth profiles assuming the temperature profile from Eq. (6). The dashed-dotted line portrays the optical depth profile of LkCa 15 obtained with the temperature profile calculated with the radiative transfer model (see Sect. 4 and Eq. (3)). The optical depth profiles have been computed assuming absorption opacities only. The vertical dashed lines indicate the rings locations as derived from the (u, v)-plane modeling.