Upper panels: Brunt–Väisälä (buoyancy) frequency profiles (orange) in two accretor models, A3-1 (left) and A3-3 (right). The right panel (i.e., model A3-3) corresponds to the one with additional Brunt bumps. The normalized Fourier spectra of the period spacings of l = 1 g modes is shown as the blue and grey lines (super Nyquist part). The vertical dashed red lines indicate the locations of the Nyquist frequency (0.5). The real peaks corresponding to the period-spacing variation are labelled by the orange squares. Note that in the Fourier spectra of A3-3 model, the dominant peak at 0.53 is above the Nyquist frequency, and its reflection at 0.47 is a fictitious peak. Lower panels: Corresponding period spacings of l = 1 g modes as a function of radial order.