1999A&A...350..197B

We present CS(J=2-1) interferometric observations obtained with the Nobeyama Millimeter Array (NMA) toward a protostar (GH2O 092.67+03.07) in the Cygnus OB7 giant molecular cloud (distance=800pc). The data clearly indicate the presence of a compact (size ≃8x10³AU) and young outflow with dynamical time scale ≃3500 year. The outflow is surrounded by a massive gas condensation. The analysis of the gas dynamics shows the signature of an infalling and rotating disk, which could be the first clear detection of such motion around a young high mass star. Single dish data obtained with the Nobeyama 45m antenna in several molecular lines are used to derive the CS abundance and the optical depth of the CS(J=2-1) toward GH2O092.67+03.07. We derive a total mass of ≃0.6M_☉ and ≃12M_☉ for the outflow and disk respectively. The comparison of the NMA data with a simple model of infalling disk indicates a mass of the central object in the range 4.0<M_*<7.5M_☉. We propose that GH2O092.67+03.07 is a dust condensation in the very early steps of forming a high mass star.