Hα variation in the selected examples. The left panel shows the spectrum that clearly displays the changes in the Hα line. The right panel visually presents the dynamic evolution of EW_Hα on short timescales, and the vertical red lines indicate the error bars. The colors of the spectral profiles in the left panel correspond to the points in the right panel, which are labeled with their respective heliocentric Julian dates, which allow a clear identification of the observation epochs.