Inverse of the quality function of the period fit in terms of the effective temperature, shown with different colors for the different stellar masses. The vertical black-dashed line corresponds to the spectroscopic T_eff of GD 358 and the vertical dotted lines show its uncertainties (T_eff = 24 000 ± 500 K; Koester et al. 2014). Analogously, the blue vertical lines correspond to the spectroscopic T_eff and its uncertainties as given by Bédard et al. (2017) (T_eff = 24 937 ± 1 018 K). Three maxima have been labeled as (1), (2), and (3), corresponding to the three asteroseismological solutions compatible with spectroscopy (see the text).