Variable absorptions in the 2740 Å Fe II line. The black line shows the reference comet-free spectrum of β Pic, obtained by averaging the unabsorbed spectra at each individual wavelength. The deep and narrow absorption near 0 km s⁻¹ is due to the stable component of the circumstellar disc of β Pic, which could be slightly blueshifted compared to the stellar radial velocity (see Brandeker 2011).