Propagation diagram for three stellar models depicting the characteristic frequencies in the interior near the lower convective boundary. The best-fitting model of Hennes is plotted alongside two models of similar evolutionary state, i.e. similar Δν value, with identical initial parameters except for a variation in [Fe/H]. The shaded region around the observed ν_max of Hennes represents the extent of the evanescent region for the three models, which increases with metallicity.