Top: a wide-field Herschel/SPIRE 250-μm far-infrared image towards the Orion B9 and NGC 2024 (Flame Nebula) star-forming regions. The image is overlaid with black contours of LABOCA 870-μm dust continuum emission. The contours go from 0.1 (~3.3σ) to 1.0 Jy beam^-1 in steps of 0.1 Jy beam^-1. The green rectangle outlines the 4′ × 4′ area mapped in ¹³CO(2−1) and C¹⁸O(2−1) in the present study. The white arrows indicate the cores which have a lower LSR velocity than the “main 9-km s^-1 part” of Orion B9 or show multiple velocity components. The Class 0 protostar IRAS 05413-0104 in the northeast corner was at the border of our LABOCA map and only weakly detected (see Fig. 1 in Paper I). Note how the Orion B9 cores are associated with a NE-SW orientated filamentary structure, and the cores with lower radial velocity (or with multiple velocity components) lie at the NE part of the structure. A scale bar indicating the 2 pc projected length is shown in the bottom left, with the assumption of a 450 pc line-of-sight distance. Bottom: a zoomed-in view of the upper image towards Orion B9. Selected cores are labelled. The LABOCA contours are as in the upper panel.