1996A&A...313..866W

We present high resolution IRAS (HIRAS) images of the HII shell G79.29+0.46, which has a faint blue star at its centre that may be responsible for the shell. We confirm that the IRAS emission is from the shell, which is detected at all four IRAS bands. The shell is clearly resolved at 12, 25 and 60µm and its size agrees within errors with the size of the radio shell. The HIRAS images show a central point source at 12µm surrounded by a faint shell, and only shell emission at 25 and 60 µm. No reliable image could be produced at 100 µm due to the strong background. We interpret the IR emission in terms of free-free emission from the stellar wind of the blue star in the centre, and dust emission from the shell. The total mass in the shell and the dust temperature are estimated to be 14M_☉ and 60-77K respectively. The shell expansion velocity is estimated at 30km/s and the mass loss rate during the shell ejection 5x10^–4M_☉/yr. A high resolution Brα spectrum shows strong emission with a line width of only 189km/s, indicating a present-day expansion velocity of the wind of 94km/s. We find a present-day mass loss rate of 10^–6M_☉/yr. G79.29+0.46 shares many characteristics with the Luminous Blue Variable AG Car.