Period evolution for a sample of low‐order pulsation modes with degree index ﹩\ell =0﹩, 1, 2, and 3. The acoustic (gravity) modes are represented by open circles (triangles). The dotted curves joining models of different ages for each illustrated mode have been obtained through spline interpolation. The ages of the models are given in Myr elapsed since the ZAEHB. Each ensemble of four panels refers to a given evolutionary sequence with parameters given in the upper left panel. The lower right ensemble provides an expanded view of the ﹩M=0.4690+0.0007﹩ M_⊙ sequence along the age axis (near 110 Myr, where helium shell burning ignites).