Initial orbital elements of ejecta particles. Each ejecta velocity corresponds to a separate simulation. The semimajor axis (a) is normalized to the semimajor axis of Dimorphos (a_dimo), and the binary orbital inclination is defined to be 0^∘. The large black dot is the orbit of Dimorphos, and the two black lines are curves of constant apocenter and pericenter that intersect the orbit. We note that these are the instantaneous orbital elements relative to the system barycenter at the beginning of the simulation, when the test particles are still at the surface of Dimorphos.