Left panel: periods of excited ℓ = 1 g modes as a function of the effective temperature, with the palette of colors (right scale) indicating the logarithm of the e-folding time (τ_e in years), for the DB WD sequence with M_⋆ = 0.584 M_⊙. Right panel: same as left panel, but for ℓ = 2 modes. In both panels, the pulsation periods of the DBV star GD 358, with the identification of ℓ according to our asteroseismological model (see Table 4), are shown as horizontal segments, where their widths represent the possible T_eff interval, according to spectroscopy.