Evolution of the orbital period of HD 25631 for different values of the initial rotational velocity (including initially synchronized rotation for a given P_ini). The tracks stop at the onset of Roche lobe overflow of the primary star. When this occurs during its main-sequence (case A) we mark it by dots, conversely, if this happens after TAMS (gray dashed line) in a case B, we mark it with crosses. For reference, the inset shows the HR diagram around TAMS, where the beginning of the RLOF phases are marked by thick black outlines. The red horizontal line visualizes the initial value of the orbital period. In these simulations we used the sync_type = “Hut_rad” tidal prescription.