Resonance crossing of a two-planet system with convergent migration. The plot shows the time evolution of (a) the outer-to-inner planet period ratio, (b) the planet eccentricities, (c) the resonant angle, and (d) the phase curve. The planet and disk parameters are m_i=1 M_⊕, m_o=10 M_⊕, τ_m=2.2 × 10⁵ yr and τ_m/τ_e=3 × 10³. The planets directly cross the 2:1 resonance at t≃6 × 10³ yr, while the inner planet’s eccentricity briefly excites to 0.01 before rapid decay. During the crossing, the resonant angle of the inner planet φ_i jumps from 0 to τ and subsequently oscillates with growing amplitude¹. In phase space, the planet’s trajectory is not captured by the resonant equilibrium. Instead, it circulates and eventually evolves toward the origin, corresponding to a low-eccentricity, non-resonant state. See https://github.com/llh-astro/resonance/raw/main/gif/no_trap.gif