Simultaneous fits of the strongest Fe I lines from excited levels. First column: the 416 cm^-1, 704 cm^-1 and 888 cm^-1 excited levels (from top to bottom). Second column: the 978 cm^-1, 6928 cm^-1 and 7377 cm^-1 excited levels (from top to bottom). Third column: the 11 976 cm^-1, 12 561 cm^-1 and 12 969 cm^-1 excited levels (from top to bottom). The stellar continuum is plotted with a green line, the intrinsic absorption profile with a blue line, and the absorption profile convolved with the HARPS instrument profile with a red line. The gas responsible for the absorption lines is defined as a unique component with the same radial velocity and line width (b value) for all the excited levels; the column densities of each excited level are independent. The positions of the absorption lines are indicated by a tick at +20.41 km s^-1 radial velocity.