  The hydrodynamic models of the protoplanetary disk, which perturbed by the
embeded low-mass companion, were calculated by our modification of GADGET-2
code. The cases of circular and eccentric orbits which can be coplanar or
slightly inclined to the disk midplane were considered. The column density of
test particles on the line of sight between the central star and observer was
computed during the simulations. Then the column density of the circumstellar
dust was calculated under the assumption that the dust and gas are well mixed
with a mass ratio 1 : 100. To research the influence of the disk orientation
relative to the observer on the circumstellar extinction the calculations were
made for four angles of inclination of the line of sight to the disk midplane
and eight directions along the azimuth. The column density in the circumstellar
and circumbinary disk were computed separately. The calculations have shown the
periodic variations of column density can arise both in the circumstellar and
circumbinary disks. The amplitude and shape of the variation strongly depend on
the parameters of the simulated system (eccentricity and inclination of the
orbit, the mass ratio of the companion and star) and its orientation in space.
The results of our simulations can be used to explain the cyclic variation of
the brightness of young UX Ori type stars.
