Echelle diagram of the power spectrum for a folding frequency Δν₀ = 155 μHz. The power spectrum was divided by the fitted background function and smoothed over five bins, i.e., 3.1 μHz. It was then divided into consecutive intervals of 155 μHz length, which were vertically stacked. The color bar indicates the power in cm² s^-2. The existence of two distinct groups of peaks separated by half the folding frequency is compatible with oscillation modes of consecutive degrees (e.g., l = 1 and l = 2).