Final semimajor axis of Callisto a_final in our migration and photoevaporation model for the case of M_CPD = 10^−6.3 (top left), 10^−6.4 (top right), 10^−6.5 (bottom left), and 10^−6.6M_⊙ (bottom right). The initial radius of the CPD is on the ordinate, and initial location of Callisto is on the abscissa. The region of excluded parameter space where Callisto already lies beyond the outer edge of the CPD and where Callisto enters the resonance is filled with gray stripes. The dotted black lines demarcate the interval where the final position of Callisto falls within 5% of its present-day position, a_final = a_JIV.