Evolution of the Ca I and Ca II line profiles (see text for details). The emission centered at about +500 km s⁻¹ in the first column (Ca I panels) is from Fe II RMT 27. The arrow in the third panel from the top indicates the second broad absorption from Ca I λ4226. The Y -axis units are in erg cm⁻² s⁻¹ Å⁻¹. The blue and red dotted lines indicate the velocity of the persistent narrow absorption (see Sect. 4.1) and of the He I absorption in the first UVES spectrum, respectively. The photometric state (min, max) of the spectra is indicated on the left of each row.