Effect of planetary companion mass on the rotational evolution of a 1.0 M_⊙ mass star. The initial rotation period of the star is three days, the star is assumed to rotate as a solid body with a core-envelope coupling timescale of 0.5 Myr; SMA_init = 0.8 R_co ≈ 3.25 × 10⁻² au. The masses of the planets are 10 M_⊕, 1 M_Jup, 5 M_Jup, and 13 M_Jup, displayed as darkish to greyish coloured lines, respectively. In the upper panel, the Roche lobe limits are displayed as long-dashed lines and the radius of the star as red dash-dotted line. The horizontal dashed line in the lower panel corresponds to the transition between the saturated and unsaturated magnetic regimes, and the circle represents the surface rotation rate of the present Sun. The time on the x-axis is given from an initial time t_init of 5 Myr.