Radial velocity curves of the eclipsing binary. The orbital phases were computed with the quadratic ephemerides (Eq. (2)). Top panel: results obtained from the He II λ 5412 and O III λ 5592 RVs. Blue symbols stand for the primary star, whilst red symbols indicate the secondary. The primary RVs of O III λ 5592 were shifted to match the systemic velocity of the He II λ 5412 line (see Table C.1). The solid and dashed curves correspond to the best-fit orbital solution based on this line. Bottom panel: full set of RV measurements along with the preferred RV curves (see Table 4). For each star, the RVs of the various lines were shifted to match the systemic velocities of the He II λ 5412 line.