Upper panel: frequencies as a function of radial order (n) for the first stage of our frequency analysis. The dotted line has a slope of 5.00 μHz, in agreement with Δν found in Fig. 5. The black diamonds are detected modes that fit into a regular structure of expected ℓ = 0 modes, red triangles mark the positions of expected ℓ = 0 modes that were undetected in our first run of CLEAN, and the two blue squares represent the detected ℓ = 0, n = 8 mode, for which the first run of CLEAN picked up the +1 d⁻¹ alias (see text). Lower panel: differences between the detected ℓ = 0 frequencies and those predicted by the asymptotic relation (Eq. (1)), also in μHz.