Secular evolution of a star–planet system composed by a 1 M_⊙ star and a 1 M_Jup planet with an initial stellar rotation period P_*,ini = 5 days and an initial semi-major axis a_ini = 0.025 AU. Red curves were computed for ω₁ = 10⁻¹⁰ rad/s and blue curves, for ω₁ = 10⁻⁶ rad/s. Top panel: semi-major axis (solid lines), stellar corotation radius (dashed lines), limit of excitation of tidal inertial waves (dotted lines), stellar radius (solid black line) and Roche limit (dashed gray line). Bottom panel: modified tidal quality factor.