Accretion rates of the first eight sink particles to form in the 10⁻² Z_⊙ run in the first ∼2 Myr. The top and bottom horizontal dot–dashed lines show the fiducial accretion rate c_s³/G evaluated at T = 100 and 50 K, respectively. The dashed red line is a fit to the first |$0.5\,\rm {Myr}$| of accretion (equation 15) with the value of fitting parameter τ shown at the top of each panel.