Left: BRITE photometry of ζ Ori during the three distinct epochs, used for the time series analysis. The color represents which nano-satellite of the BRITE-Constellation monitored ζ Ori: magenta for UBr, cyan for BAb, red for BHr, and blue for BLb. The regions having non-periodic events, which were excluded for a dedicated analysis, are marked in black (see text). Right: corresponding Lomb-Scargle periodograms of the full lightcurves. No significant periodic variability was found outside the region of 0 to 1  d^-1. Variability is marked in parts per thousand (ppt).