Time derivative of the planetary spin rate Ω₂ in our generic binary system as a function of α = a₁∕a₂. Each panelassumes different eccentricities for both orbits. Broad gray curves show results from semi-analytical calculationsand predictions from analytical models are depicted in thin lines. Values obtained with our original (Zoppetti et al. 2019a) are presented in blue, while the colors correspond to our current model with different orders in α. See inlaid box in left-hand plot for details.