Continuum images of HerBS-89a at 1.2 mm, resulting from merging the lower and upper side bands of the two sets of NOEMA observations obtained with natural weighting of the visibilities (see Sect. 3.1.1 for further details). Contours are at 5, 10, 20, 40, 80σ levels. North is up, east is left. Left: high-angular resolution continuum image at 254.6 GHz with a beam size of . Right: lower-angular resolution image at 220.8 GHz with a beam size of . The synthesized beam is shown in the lower left corner of each image, and the cross indicates the position of the phase center (RA 13:16:11.52, Dec +28:12:17.7). The weak source HerBS-89b, about to the east, is detected at both frequencies; the position of the source is indicated with an arrow and further details are provided in Sect. 3.1.1.