Example of the modelled spectrum (the blue line) and the corresponding continuum (the orange line). The dashed black line shows the zero flux level. The spectra were calculated using the best-fit T–P profile in Fig. 5. The continuum corresponds to the blackbody spectrum at the temperature of T₂. In the HARPS-N wavelength range (i.e. below 0.69 μm), the flux at the Fe I line core is much larger than the continuum flux.