Variations in the frequency content of the MOST light curve of HR 8799. Fourier amplitude spectra of the first (grey/red full line), middle (grey/green dash-dotted line) and last (black/blue dashed line) third of the data are plotted with curves in the positive amplitude range, while the frequency components identified in the respective time segments, down to the 4σ level, are plotted with vertical lines in the negative amplitude range. The horizontal lines at the lower end of these lines are added only for better visibility of the overlapping lines.