Most dominant frequencies of the CDS f_CDS normalised by the eigenmode f_κ = 0.51 × 10^-3   d^-1 (triangles), periodically excited with various stellar pulsation periods P but fixed amplitude Δu = 1.0   km   s^-1, at the dust nucleation zone r ≈ 2.5   R_∗. The set of eigenfrequencies are indicated by circles. The eigenperiod is labelled with P_κ. The excitation frequencies lie on the solid line and their harmonics on the dash-dotted lines. The grey line separates the irregular (left) from the pulsation-dominated domain (right).