Tidal evolution of the PC binary, for A = 10 and a logarithmic mass accretion of Charon during the first 10⁴ yr, starting with the initial eccentricity e_C = 0.001. Panels show the orbital semi-major axis, a_C, in units of R_P (panel a), the orbital eccentricity, e_C (panel b), and the spin angular velocities of Pluto, Ω_P (panel c) and Charon, Ω_C (panel d) in units of the mean motion, n_C. Each colour represents a different initial P₀, in units of days.