Combined cross-correlation function (CCF) as a function of planet radial velocity (RV), semi-amplitude, and RV shift of the Na doublet. The CCF has been expressed in the form of signal-to-noise ratio (S/N). The green dotted lines indicate the expected RV semi-amplitude and zero velocity. The black plus sign shows the location of the maximum CCF. The top panel shows the CCF at the expected RV semi-amplitude, corresponding to the horizontal green dotted line.