Evolution of the asymptotic period spacing for dipole modes computed from the right-hand side of Eq. (2) versus X_c for models with masses 2.5 M_⊙, 3.2 M_⊙, and 3.8 M_⊙, each for Z_ini = 0.020. The solid lines correspond to models without overshooting, while the dashed lines correspond to models including core overshooting with a value of f_ov = 0.03. The thin grey bar highlights the measured period range of 5048 to 5907 s for KIC 10526294 from Table 1; see also Fig. 1. All models were computed using OPAL opacity tables, and the Nieva & Przybilla (2012) and Przybilla et al. (2013) mixture.