Periodogram of ξ Tau from the TESS (top) and MOST 2012 (bottom) light curves. We removed eclipses and computed five Fourier transforms (Lenz & Breger 2005), with fitting of frequencies, amplitudes and phases, and subtracting the respective model, ∑_iA_isin[2π(f_it + ϕ_i)]. For TESS, the dominant frequencies were 1.407, 2.371, 1.421, 2.814, and 0.279 d⁻¹. We note f₄ = 2f₁ and f₅ = 2f_orb of the inner orbit. For MOST 2012, on the contrary, we found 2.369, 2.216, 0.993, 0.282, and 2.839 d⁻¹. The non-existent 1.407 d⁻¹ frequency is labeled “ftess”.