Accretion efficiency in the weak and strong coupling regime. When the Bondi time t_B = GM/Δv³ is equal to the particle’s friction time t_f, the drift accretion radius r_d peaks and equals the Bondi radius r_B. For a particle of fixed size, the ratio t_B/t_f on the horizontal axis increases as the core mass grows in time. When particles are strongly coupled to the gas (t_B > t_f), with respect to the gravitational attraction of the core, the drift radius decreases as (the analytical scaling of Eq. (27) is indicated with a full grey line). Near t_B/t_f ≈ 10^-2 the drift radius rapidly decreases. The inset shows particle trajectories (grey curves) in this regime, which can be compared with those at t_B/t_f = 1 (black curves). Where the former are simply gravitationally deflected, in the latter case we see that particles inside the Bondi radius (marked by a red circle) are accreted by the central point source.