2D Na model convolved with the broadening kernel outlined in Sect. 3.2. Upper left: rotational broadening kernel outlined in Eq. (1). The solid lines red and blue curves show the final morning and evening halves, respectively, after convolution with an instrumental profile, shown in grey. Upper right: asymmetric Na model, with varying broadening and atmospheric parameters between the morning and evening limbs. The combined model is overplotted with a dashed black line. Middle: 1D model projected to a 2D orbital phase vs wavelength array for a single ESPRESSO order. This array is then weighted by the limb-darkening model described in Gandhi et al. (2022). This ensures solely morning or evening contributions during ingress or egress, respectively. Lower: 2D orbital phase vs wavelength array after SYSREM model filtering, highlighting the distortions of the planetary lines after preprocessing. The dotted black curve shows the planetary velocity to which the model is projected.