A. Lomb Scargle (LS) periodograms of all epochs of 2M J0746+20B, after subtraction of the primary’s 3.32 hours period: power spectra vs. frequency days⁻¹. Dashed, horizontal red lines denote the 5σ false alarm probability of the peaks. The period obtained for the combined dataset is 2.14 ± 0.11 hours, a newly discovered optical period. This periodicity lies within the period uncertainty range of Berger et al. (2009), Lynch et al. (2015) and Zhang et al. (2020) who measured the radio period at 2.072 ± 0.001 hours, 2.071481 ± 0.000002 hours and 2.1 ± 0.1 hours, respectively, as well as being consistent with the 2.07 hours period of quasi-sinusoidal Hα emission (Berger et al. 2009). B. The same LS periodogram, zoomed into the area around the highest peak. The dashed red line corresponds to our detected optical secondary period of 2.14 ± 0.11 hours.