We calculate the flux received from a binary system obscured by a circumbinary disc .
The disc is modelled using two dimensional hydrodynamical simulations , and the vertical structure is derived by assuming it is isothermal .
The gravitational torque from the binary creates a cavity in the disc ’ s inner parts .
If the line of sight along which the system is observed has a high inclination I , it intersects the disc and some absorption is produced .
As the system is not axisymmetric , the resulting light curve displays variability .
We calculate the absorption and produce light curves for different values of the dust disc aspect ratio H / r and mass of dust in the cavity M _ { dust } .
This model is applied to the high inclination ( I = 85 \degr ) eclipsing binary CoRoT 223992193 , which shows 5–10 % residual photometric variability after the eclipses and a spot model are subtracted .
We find that such variations for I \sim 85 \degr can be obtained for H / r = 10 ^ { -3 } and M _ { dust } \geq 10 ^ { -12 } M _ { \sun } .
For higher H / r , M _ { dust } would have to be close to this lower value and I somewhat less than 85 \degr .
Our results show that such variability in a system where the stars are at least 90 % visible at all phases can be obtained only if absorption is produced by dust located inside the cavity .
If absorption is dominated by the parts of the disc located close to or beyond the edge of the cavity , the stars are significantly obscured .