(V/R)_wing ratio measurements of the double-peaked emission features after subtracting a star model shown on the x-axis. The observation date is plotted on the y-axis. In the left panel for B243, the EW is determined between ±100 km s⁻¹ and ±300 km s⁻¹; in the middle panel for B268, it is between ±90 km s⁻¹ and ±290 km s⁻¹, and in the right panel for B275, it is between ±90 km s⁻¹ and ±240 km s⁻¹.