INFRARED IMAGING AND SPECTROSCOPY OF G79.29+0.46

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 responsib le 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 resolv ed at 12, 25 and 60 mu m and its size agrees within errors with the si ze of the radio shell. The HIRAS images show a central point source at 12 mu m surrounded by a faint shell, and only shell emission at 25 an d 60 mu m. No reliable image could be produced at 100 mu m 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 dus t emission from the shell. The total mass in the shell and the dust te mperature are estimated to be 14 M(.) and 60-77 K respectively. The sh ell expansion velocity is estimated at 30 km/s and the mass loss rate during the shell ejection 5 10(-4) M(.)/yr. A high resolution Br alpha spectrum shows strong emission with a line width of only 189 km/s, in dicating a present-day expansion velocity of the wind of 94 km/s. We f ind a present-day mass loss rate of 10(-6) M(.)/yr. G79.29+0.46 shares many characteristics with the Luminous Blue Variable AG Car.