Analysis of the optical data. Top: TESS light curve of VHS J1256-1257AB. Vertical lines denote individual uncertainties, and the red line is a 601-point median filter. The zero time corresponds to MJD 58568.93734. Middle: LS periodogram for the TESS light curve shown in the top panel (gray curve) and after detrending with a median filter (orange). The window function is also shown (cyan). We computed the associated 99.9% FAP (red) from 10 000 light curves generated by data randomization. Bottom: LS periodogram for different chunks of the data. A double peak centered at ∼2.1 h is present in all the sections of the data.