Joint fit to HD 209458 intrinsic sodium doublet, shown for epoch 2 as a function of wavelength in the star rest frame (in abscissa) and orbital phase (in ordinate). Green dotted lines are transit contacts. Top panel: intrinsic spectra, colored with flux. Stellar lines kept to solar abundance were excluded from the fit (shaded regions). Middle panel best-fit theoretical model. Bottom panels: residuals over the full epoch, calculated as in Fig. 28.