Collapse simulations with 100 nm grains using the terminal velocity at the formation of the first hydrostatic core (~60 kyr). The HLLD solver (Miyoshi & Kusano 2005) is used for the (gas-dust) monofluid. Gas density is on the left (slice), which is a reference for other simulation runs as long as the feedback of the dust remains weak. Mesh-refinement levels are displayed with the contours. White arrows indicate the gas velocity. Corresponding dust-to-gas ratio map on the right, as predicted by the terminal velocity implementation.