Upper panel: the synchronization parameter n/Ω vs. the effective temperature of the star T_eff in transiting planetary systems with T_eff ≥ 6000 K. WASP-12 with n/Ω ≈  33 has been omitted for the sake of clarity; lower panel: an enlargement of the lower portion of the upper panel to better show the domains close to n/Ω = 1 and n/Ω = 2, which are marked by horizontal dashed lines. The names of the systems are reported in both panels, although they are omitted for n/Ω ≤ 4.0 in the upper panel to avoid confusion.