Radial velocity curves of the red gaint (top) and hot (middle) components folded with period P_sp = 918^d. SALT/HRS and FEROS data are shown with filled and open circles, respectively. Solid lines show synthetic radial velocity curves for the case of the eccentric orbit and dashed lines in the case of a circular orbit. The horizontal lines represent the systemic velocities for the eccentric (solid) and circular (dashed) cases. The lower middle panel shows the jet centre velocity VC_J. The bottom panel presents the radial velocities of the emission line wings: Hα (circles), Hβ (diamonds), He Iλ5875.6 Å (asterisks), He IIλ5411.5 Å (triangles) and the mean value from He Iλ5875.6 Å, and λ7065.2 Å lines (squares), respectively, compared to the radial velocity curve of the hot component (blue line). The method described by Shafter (1983) and references therein were used to measure the velocities of emission lines wings.