From top to bottom: V/R variations and peak separation (Hα, Hβ), position, depth, and asymmetry of the central absorption (Hβ, Hγ, Hδ) as a function of time, expressed in Julian Days. The V/R maxima are indicated by vertical dotted lines. The regions in gray mark the triple-peak phases. Black, red, blue, and green symbols correspond respectively to Hα, Hβ, Hγ, and Hδ measurements. The black solid lines in panel b) are linear regressions applied to Hα peak separation.