Left: YS coefficient as a function of the secondary-to-primary size ratio. The primary asteroid has a radius of 1 km. The orbital period is 12 hours, and the spin periods of both components are 8 hours. The ratio of the primary-to-secondary YS coefficient is indicated by red triangles. The solid red line represents the best-fit curve: f_YS, p/f_YS, s = (r_s/r_p)^1.80. The dashed red line shows the theoretical formula without accounting for the non-linear effect of partial eclipses: f_YS, p/f_YS, s = (r_s/r_p). Right: Value of α as a function of the frequency ratio and thermal inertia. The dashed black line represents the theoretical value, excluding the non-linear effects of partial eclipses. For a typical small binary system with Γ ∼ 200 tiu and a primary spin period of approximately three hours, α is around 1.8.