Spectroscopic orbit of planet d. The RV residuals from HIRES (“pre” and “post” upgrade), Levy/APF, and HARPS-N are phase-folded at the orbital period 12.458 days (colour code in the legend, same as in Fig. 5). The residuals are calculated by subtracting the activity-induced term and the signals of planet b and c from the original data, using the results in Table 3. The black solid line represents the best-fit spectroscopic orbit of planet d, while black dots indicate the binned RVs and the error bars represent the RMS of the data in each bin.