Evolution of the 250 GHz flux from IRAM 30-m telescope (red dots, Altenhoff et al. 2009) and PdBI data (black dots). PdBI 90-GHz fluxes were converted to 250 GHz fluxes, applying a conversion factor of 22.1 determined by thermal modelling. The beam size is HPBW = 11″ for the 30-m data and  ~6″ for the PdBI data. The observed core (Table 7) and shell emissions on 27−28 October are shown by opened circles and triangles, respectively. The dotted-dashed line shows the model for the shell emission (q = −4, a_max = 100 mm, V₀ = 85 m s^-1) with HPBW = 6″ for the two first dates, and 11″ later on. Two-component models (shell+core) are shown with solid, dashed and dotted lines, with the core parameters being q = −3.2 and (a_max = 100 mm, V₀ = 5 m s^-1), (a_max = 100 mm, V₀ = 9 m s^-1), and (a_max = 10 mm, V₀ = 7 m s^-1), respectively.