Results from the two-dimensional Gaussian fit to the C¹⁸O channel maps. Left: Best fit central positions with respect to the image plane, where their colors represent the velocity of the channel v_LSR. The dashed lines represent the position of the barycenter. The ellipse centered at the barycenter represents the beam size (FWHM). Right: C¹⁸O emission velocity with respect to the protostar’s v_LSR versus distance from the protostar. Blue dots are obtained from the C¹⁸O emission blueshifted with respect to the protostar and red dots from the redshifted emission. Faded dots come from velocity channels with considerable extended emission, and therefore their properties are affected by motions other than Keplerian. The solid black lines are the Keplerian rotation profiles for 0.1, 0.2 and 0.3 M_⊙.