Evolution of the stellar surface-rotation rate (top panel), stellar Rossby number (middle panel) and X-ray luminosity (bottom panel), under the impact of planetary inward migration. For the stellar initial surface rotation rate we considered the following values Ω_in = 1, 2, 3.2, 4, 5, 6, 7, 8, 9, 10, 18 Ω_⊙, for the planetary mass M_pl = 1 M_J, and initial planetary orbital distance a_in = 0.02 AU. The meaning of the other quantities is the same as in Fig. 3.