2D view of the first hydrostatic core evolved into a rotationally supported disc at 1221 yr after its formation as a result of the fiducial collapse of a 1 M_⊙ pre-stellar core with an initial rotation rate of Ω₀ = 1.77 × 10⁻¹³ rad s⁻¹ (same time snapshot as Fig. 2). The dust size is fixed to a constant value of 1 µm. The four panels show the (a) Stokes number, (b) gas temperature, (c) gas density, and (d) radial gas velocity within the inner 15 au of the 3000 au collapsing pre-stellar core. The gas velocity streamlines indicate the material falling onto the disc and the mixing within. The meridional flow exhibited in the plot between 5−10 au forms in the inner regions and travels outwards. This motion results in an outward transport and retains dust in the outer disc.