HD 172555’s light curve after the removal of δ Scuti variations with different degrees of precision (see text). From top to bottom: raw light curve (black), the ten dominant frequencies subtracted (blue), and the oscillations subtracted with S/N > 10 (orange), S/N > 8 (green), S/N > 6 (red), and S/N > 4.8 (purple). The vertical scale is common to all curves, allowing for the effect of the different δ Scuti removal schemes on the residuals’ amplitude to be compared.