Dependence of the tidal torque constant E₂ on the input physics for a 5 M_⊙ model. The solid (black) line corresponds to our standard Z = 0.02 model, the red-dotted, green-dashed and blue-long-dashed curves refer to the overshooting models with parameters α = 0.05, 0.1 and 0.2, respectively. For illustration, we also plot the 5 M_⊙, Z = 0.0001 (cyan-dot–short-dashed line), Z = 0.004 (magenta-dot-long-dashed line) models with no core overshooting as well as the result of Claret (2004) for M = 5 M_⊙, Z = 0.02 (orange, short-long-dashed). The mid and bottom panel display the evolution of radius and mass of the convective core for these models.