Variability of the Fe II 6149 Å lines. Top: 2012 Narval line profiles overplotted for Fe II 6149 Å. Middle: periodogram based on EWs measured from the profiles shown in the top panel. The red line is for the observations and the blue line for the window function. Bottom: magenta circles represent EWs measured from the 2012 Narval spectra using the Fe II 6149 Å line and are phased with P = 51.1 d. The obtained period is slightly shorter than the one obtained from the mean longitudinal magnetic field measurements, but within the errors still similar. The sinusoidal fit is shown with the red line.