Azimuthally averaged radial intensity profile of H₂CO 3_1,2 − 2_1,1 (blue), CS 5−4 (green), and CN 2−1 (brown; blending of the three components at 226.87 GHz reported in Table 1) in mJy beam⁻¹ km s⁻¹ (left axis), and of the 1.3 mm continuum (red) in mJy beam⁻¹(right axis). The radial distance is indicated in au on the bottom axis and arcseconds on the top axis. The angular resolution of the lines/continuum profiles is indicated by the corresponding horizontal lines. The shaded areas indicate the dispersion of the intensity values around the mean along each annulus in the radial direction. The vertical dashed lines indicate the position of the CO snowline (black), and of the peaks of the emission in H₂ CO 3_1,2 − 2_1,1 (blue), CS 5−4 (green), and CN 2−1 (brown).