Top: EW of the fluorescent Fe Κα line contributed by the Be decretion disc in the star-disc interaction scenario as a function of R_s for different values of Z_s. Bottom: EW contours for the same scenario as a function of R_s and Z_s. The primary source is modelled as a uniform axisymmetric ring of radius R_s from the polar axis of the Be star and of altitude Z_s above the equatorial plane of the Be star. The hatched area in the bottom part corresponds to the scale height of the Be decretion disc.