The IRAS01425+2902 wide binary system was recently reported to have both a young planet and a puzzling geometric arrangement, where the planet and binary both orbit edge-on, but misaligned by 60^◦ to the circumprimary disc. This is the youngest transiting planet yet to be detected but its misalignment to the disc is difficult to explain. In this paper we explore the dissolution of an unstable triple system as a potential mechanism to produce this system. We simulate the effects of an ejection interaction in models using a highly inclined, retrograde flyby centred on the primary star of IRAS01425. The escaping star of ∼ 0.35 M_☉ inclines both the disc and binary orbits such that they have a relative misalignment of ≳ 60^◦, as inferred from observations. The planet orbit also becomes inclined relative to the disc, and our interpretation predicts that the binary should have a highly eccentric orbit (e ≳ 0.5 from our simulations). We additionally demonstrate that despite the high relative misalignment of the disc it is unlikely to be vulnerable to von Zeipel-Kozai-Lidov oscillations.

Context. GG Tau is one of the most studied young multiple stellar systems: GG Tau A is a hierarchical triple surrounded by a massive disc and its companion, GG Tau B, is also a binary. Despite numerous observational attempts, a comprehensive understanding of the geometry of the GG Tau A system is still elusive. Given the significant role of dynamical interactions in shaping the evolution of these systems, it is relevant to characterise the stellar orbits and the discs' properties. Aims. To determine the best orbital configuration of the GG Tau A system and its circumtriple disc, we provide new astrometric measures of the system and we run a set of hydrodynamical simulations with two representative orbits to test how they impact a disc composed of dust and gas. Methods. We tested the dynamical evolution of the two scenarios on short and long timescales. We obtained synthetic flux emission from our simulations at different timescales and we compared them with multi-wavelength observations of 1300 μm ALMA dust continuum emission and 1.67 μm SPHERE dust scattering to infer the most likely orbital arrangement. Results. We extend the analysis of the binary orbital parameters using six new epochs from archival data, showing that the current measurements alone (and future observations coming in the next 5- 10 yr) are not capable of fully breaking the degeneracy between families of coplanar and misaligned orbits, but finding that a modest misalignment is probable. We find that the timescale for the onset of the disc eccentricity growth, τ _ecc, is a fundamental timescale for the morphology of the system. Results from the numerical simulations obtained using the representative coplanar and misaligned (Δ θ = 30) orbits show that the best match between the position of the stars, the cavity size, and the dust ring size of GG Tau A is obtained with the misaligned configuration on timescales shorter than τ _ecc. The results exhibit an almost circular cavity and dust ring, favouring slightly misaligned (Δ θ ∼ 10- 30) low-eccentricity (e ∼ 0.2- 0.4) orbits. However, for both scenarios, the cavity size and its eccentricity quickly grow for timescales longer than τ _ecc and the models do not reproduce the observed morphology anymore. This implies that either the age of the system is shorter than τ _ecc or that the disc eccentricity growth is not triggered or dissipated in the system. This finding raises questions about the future evolution of the GG Tau A system and, more generally, the time evolution of eccentric binaries and their circumbinary discs.