Orbital period ratio (p + 1) /p + Δ_{(p + 1) /p} as a function of the period of the inner planet, as predicted by expression (14) for flared disks with H₀ = 0.05, α = 1, and f = 0.25. Top panels: represent the 2:1 MMR while bottom plots represent the 3:2 resonance. Each graph assumes a different value for the mass (in units of m_⊕) of the inner planet, whose value is indicated in the top right-hand corner. Colored curves correspond to different mass ratios: m₂/m₁ = 1.6 (green), m₂/m₁ = 1.7 (blue), m₂/m₁ = 1.8 (purple), and m₂/m₁ = 2 (orange). Open black circles denote the distribution of confirmed planets.