Channel map of H¹³CO⁺ 1 →0 emission (contours in K km s⁻¹ from 0.25 to 1.75 in steps of 0.25) obtained with the IRAM 30 m telescope. The background image is the Subaru IR image from Fig 1. The blue contour is the 3 Jy level of the SHARC 350 μm emission. The star marks the position of the binary system S106 IR; the dashed red line indicates the run of the dark lane, i.e. thepossible accretion flow.