Evolutionary tracks in the HR diagram for single star models and close binaries. The four panels correspond to different initial masses for the single star or for the primary in the close binary (in that case, the secondary has a mass equal to 2/3 the primary mass). The masses, the initial metallicities (Z), and the approximate initial surface velocities on the ZAMS are indicated. For the precise initial surface rotation of each model, see the values in Tables A.1 and A.2. For a given initial mass, the three upper panels correspond to spin-down cases, while the three lower panels correspond to spin-up cases.