Radio observations and the mass flow rate of αCyg (A2Ia)

From the free-free excess at 10μ Barlow and Cohen (1977) derived a mass loss rate of 6.9 x 10-7 solar masses yr-1 for αCyg. They predicted a 10 GHz radio flux of 2.2 mJy. On the other hand Praderie et al. (1980) derived a considerable lower mass loss rate of 1.1 x 10-8<=M<=7 x 10-8 solar masses yr-1 from a curve of growth analysis of the envelope ultraviolet FeII-lines of αCyg. Radio observations are desirable to make a decision about these discrepant results. Therefore the authors observed αCyg at 15 GHz with the 100 m telescope of the MPIfR at Effelsberg. The observations are discussed together with recent VLA data of Abbott et al. (1980). (Auth.)