The transfers capable of producing the present orbits of Halimede (left panel) and Nereid (right panel). Lower curve corresponds to the minimum impactor speed v_im and an impactor mass m_i = 1 m_⊕. Intermediate curve corresponds to the maximum impactor speed v_iM and m_i = 1 m_⊕. Upper curve corresponds to v_im and m_i = 3.5 m_⊕. The maximum current eccentricity e_max is shown by a dotted line. For Halimede the upper curve and e_max overlap. A (B) is the square of the ratio of the satellite’s speed just before (after) the impact on the escape velocity at the satellite’s location just before (after) the impact. e_1m (e_2m) is the minimum eccentricity of the orbits before (after) collision.