Top panel: The blue points (planets h to b, left to right) are the observed orbital frequencies P⁻¹ (where the P’s are the planets’ orbital periods, see Table 1) as a function of the series of integers n = [2, 3, 4, 6, 9, 15, 24]. When applying a linear fit (green line), the slope corresponds to a period P₀ = 0.09 yr. Bottom panel: plot of as a functionof n, showing a residual frequency corresponding to a period of ~1.3 yr.