MEGNO stability map depicting the upper mass limit (within ±1σ (68.3%), ±2σ (95.4%), and ±3σ (99.7%) confidence intervals) of an injected hypothetical perturber in the WASP-19 system. The red horizontal dashed lines represent the perturber’s mass range between M = 400 M_⊕ and M = 1.4 M_⊕ determined from the RV constraints (Bernabò et al. 2024). The red vertical dashed lines from left to right represent the perturber’s unstable orbits in 2:3, 1:1, and 3:2 resonances with WASP-19b determined in this paper, while the black vertical dashed lines from left to right represent the perturber’s stable orbits in 1:2, 5:3, 2:1, 5:2, and 3:1 resonances with WASP-19b found by Cortés-Zuleta et al. (2020).