Tidal evolution calculations for SW CMa, following the prescription by Hut (1981). The vertical dotted line in each panel represents the current evolutionary age of 680 Myr (log τ = 8.833), based on the models by Claret (2004). a) Eccentricity as a function of time; b) Orbital period; c) Normalized angular rotation rate of each star. The dot-dashed line represents the evolution of the pseudo-synchronous value, and the horizontal dotted line is the pseudo-synchronous rate at the present age. d) Angle between the equator of each star and the plane of the orbit. The four curves correspond to different initial values as given in the next panel. e) Theoretical projected rotational velocity of the primary as a function of time, for four different initial values of the spin-orbit angle, φ₀. The measured vsini_rot and its uncertainty are indicated with the horizontal dashed line and shaded area. Theory agrees with observation at the current age of the system. f) Same as e), for the secondary. In this case theory is not able to match the observation, regardless of the initial values assumed for Ω/Ω_orb and φ.