Evolution of the surface velocity as a function of the logarithm of the surface gravity. Dotted (black) lines are for stars without engulfment. Cases for Ω / Ω_ini = 0.1 and 0.5 are shown. The black long-dashed line (labelled V_max) corresponds to solid body rotation without engulfment starting with an initial rotation near the critical velocity (see text). Continuous lines correspond to cases with planet engulfment for stars with an initial velocity equal to 10% the critical value and the short-dashed lines correspond to the same cases but for an initial rotation equal to 50% of the critical value. The different colours for solid and dashed lines are for planet masses of 5 (red), 10 (magenta), and 15 M_J (blue) and initial orbital distances of 0.5, 1, and 1.5 au from left to right (see labels). The different panels are for different values of the mass of the star. In the case of 2.5 M_⊙, the evolution is pursued until the end of the core He-burning phase, while for lower initial mass stars, the evolution is stopped at the tip of the red giant branch.