Zoomed-in view of the STIS spectra of β Pic from April 29, 2025, around two Fe II lines. Top: view of the strong Fe II line at 2756.5 Å. Archival STIS spectra of β Pic covering the same line are shown in transparent font. The solid black line represents an estimate of the stellar photospheric continuum, free of circumstellar absorption. Bottom: same view of the shallower Fe II line at 2578.7 Å. This wavelength region is covered by two orders of the STIS echelle spectrograph. Since these two lines arise from excited states of Fe⁺, they do not show any signature of the circumstellar disc (see Sect. 2.3).