Variation in the terms ℓ/2 − d_0ℓ measuring the location of non-radial modes with respect to radial modes (Eq. (10)) in abscissa, with the observed large separation in ordinate. The term d₀₀ in red, close to zero, indicates that the fit of ε_obs(Δν_obs) is unbiased; 0.5−d₀₁ in blue shows a wide spread that may indicate the presence of mixed modes; −d₀₂ is plotted in green. The size of the symbols is proportional to the percentage of energy in a given degree. The dashed lines correspond to the fits proposed in Table 1, plus or minus the frequency resolution.