Instabilities unfolding. Semimajor axes and perihelion–aphelion envelopes for four representative disintegrations: during the mass-loss epoch (orbit crossing while the Sun is still losing mass); promptly after white dwarf formation (Saturn scattered and ejected within 2.5 Myr, leaving Uranus and Neptune locked in a phase-protected 2:1 resonance); delayed by 0.2 Gyr (Uranus–Neptune crossings from ∼0.1 Gyr; Neptune ejected at 0.2 Gyr); and delayed by 1.2 Gyr (Uranus–Neptune exchange at 1.24 Gyr, Neptune ejected at 1.32 Gyr).