Two-dimensional map of the modelled CLV and RM effects of HD 209458 system around the Na I lines after dividing all stellar models by the out-of-transit spectrum, shown in the stellar rest frame. Top panel: model containing only the RM effect. Middle panel: model containing only the CLV effect. Bottom panel: model containing both the RM and CLV effects. The black solid lines show the calculated position of the planetary trail extrapolated to the out-of-transit time for better visualisation of the in-transit residuals. The horizontal dashed lines show the four contacts of the transit. The colour bar describes the relative flux (F_in ∕F_out − 1) in %.