Dipole (ℓ = 1) average of the computed period spacings, , assessed in a range of periods that includes the periods observed in NGC 2371, shown as solid (dashed) curves corresponding to stages before (after) the maximum T_eff for different stellar masses. The location of NGC 2371 when we use the effective temperature derived by Ciardullo & Bond (1996), T_eff = 135 000  ±  10 000 K, and the period spacing Δ Π = 14.5312 ± 0.0226 s derived in Sect. 3.5, is highlighted with a magenta circle. The stellar mass derived from linear extrapolation is M_⋆ ∼ 0.760 M_⊙ if the star is before the maximum T_eff, and it is M_⋆ ∼ 0.856 M_⊙ if the star is after the maximum T_eff.