Difference between RV measurements made on the perturbed and unperturbed spectra δ(RV) = (RV)_p − (RV)_u for He i λ 4921 (open triangles), He i λ 5875 (filled-in triangles), Si iii λ 4552 (stars) and Hβ (squares). Also shown is the shape of the perturbed (dash) and unperturbed (dots) RV curves for He i λ 5875 after down-scaling by a factor of 10 for illustration purposes. The perturbation leads to a RV curve corresponding to a more eccentric orbit than the actual orbit.