¹²CO(2−1) line emission, channel maps (Jy beam⁻¹ ) in the central |x,y|<2 arcsec square. The central LSR velocity is indicated in each panel (before subtraction of the 10 km s⁻¹ systemic velocity of the star). Two examples of possible arcs seen in successive channel maps are circled in blue (at 8–8.5 km s⁻¹ and 13-13.5 km s⁻¹, respectively). Close to the star, within ~0.5 arcsec from its centre (Figs. 16 and 17), there is evidence for the presence of a reservoir of ¹²CO gas, possibly partly gravitationally bound, with an rms Doppler velocity of ~2–3 km s⁻¹. There is also evidence for an enhancement of emission at large values of V_z , where it is seen to cover dominantly the north-western red-shifted octant. Both features have been discussed in Sect. 3. The contours are at 3, 10 and 20 times the noise level (see Table 1).