Outcome of the scattering of two giant planets initially on circular orbits with semi-major axes near 10 au in the conservative (i.e. non-dissipative) case. The few systems that kept their two planets over 5 × 10⁶ yr are displayed in grey (≲1% of the systems). Other systems evolved into one-planet systems typically after 10⁵ yr, either through planet–planet collision (≈63%; red), ejection of the other planet (≈36%; blue), or collision of the other planet with the star (≈1%; orange). The yellow line is the predicted orbit of the remaining planet after an ejection for typical values (see Eq. (9)). To the right of the black line are planets whose apocentre is above 90 au (projected distance of HIP 65426 b) and the grey line shows the orbits whose pericentres are at 15 au, which is the detection limit of an eventual companion of mass m_p ≳ 5 M_J to HIP 65426 b (Chauvin et al. 2017).