Dynamical status at the end of an example of a simulation of the dynamics of the TWA 7 planetary system with two planets, TWA 7 b (red), an additional planet TWA 7 c (blue), and the disk of planetesimals. The initial orbital parameters of TWA 7 b are m_b = 0.3 M_Jup, a_b = 52 au (Lagrange et al. 2025), and e_b = 0, consistent with the constraints derived in Sect. 2. In this example, the initial orbital parameters of TWA 7 c are m_c = 0.4 M_Jup, a_c = 18 au, and e_c = 0. Left : view of the system from above. The planetesimals are depicted with small black dots, and the orbits of the planets are indicated with dashed colored lines. Middle : view of the system in terms of semi-major axis and eccentricity. Right : radial profile of the planetesimal disk (solid black line) superimposed to the observations of Ren et al. (2021) (green dotted line). This configuration reproduces the observed inner edge of the disk while preserving a population of horseshoe co-orbitals along the orbit of TWA 7 b.