Confidence contours for the best-fit parameters obtained from the adjustment of the primary RV data of CPD-41° 7742. The best-fit solution is shown in each panel by the black filled dot. The corresponding 1σ confidence level is shown by the blue contour. For comparison, the value of the apsidal motion rate (respectively eccentricity) and its error bars as derived in Sect. 6 are shown in orange (respectively pink) respectively by the solid and dashed lines.