Inverse of the quality function of the period fit considering ℓ = 1 modes only in terms of the effective temperature for VV 47 assuming that the star is before the knee for three different sets of periods (see text for details). The vertical wide strip in gray depicts the spectroscopic T_eff and its uncertainties. The curves have been arbitrarily shifted upward (with a step of 0.02 for the left panel, 0.025 for the middle panel, and 0.04 for the right panel), except for the lowest curves. It is possible to adopt a model with M_⋆ = 0.530 M_⊙.