Time variation of the log(g) of model stars of mass 2.5 M_⊙ (blue lines) and 2.6 M_⊙ (red lines) calculated by assuming ζ = 0.03 and ζ = 0.04. The coloured regions indicate the error associated with the derivation of the surface gravity for the two components of Capella (pink – primary, cyan – secondary) given in Torres et al. (2015). The right panel shows a zoom in of the black box in the left panel, and the thick sections of the red and blue lines highlight the simultaneous fit of both components.