Evolution of sdBs produced via binary evolution for (M_1i, q_i) = (0.79 M_⊙, 1.5). The thick gray line identify overlapping evolutionary tracks (there are five tracks overlapping in this figure, see text for details). Panel a: evolutionary tracks in the T_eff − log g plane. Each linestyle corresponds to a different set of (M_c, M_e, P_orb) at the start of stable CHeB (see legend). Panel b: rate of period change, r, versus pulsation period, P, for the models in panel a. The final orbital periods for these models are ∼1400 days. Observations are the same as in Fig. 1.