FeIIλ4576.3 absorption line of TIC 167124706 at three different epochs. The bisector of the line is shown in red and is calculated with respect to the smoothed spectrum shown in blue. The smoothed spectrum is generated by a moving average using the window length of three data points. The top axis shows the Doppler velocity with respect to the central wavelength of the absorption line indicated with the vertical dashed line. The spectrum is not corrected by redshift. Observation dates, spectral resolutions, and signal-to-noise ratios are listed in the insets.