Massive Stellar Content of the Cygnus Superbubble

The Cygnus superbubble is one of the largest bubbles known in the Milky Way galaxy so far. It has been identified by its strong X-ray emission and its angular size is approximately 18 by 13 degrees in Galactic longitude and latitude, respectively. It is still unclear whether the Cygnus superbubble is a physical unity of interstellar matter, or a projection along the line of sight of unrelated features at different distances.The superbubble has seven OB associations containing numerous young massive OB stars. Since in this direction the line of sight is along the local Orion spiral arm, the discrimination of individual stellar and interstellar structures is difficult. Thus, the available distance determinations to the OB-star groups within the boundaries of the Cygnus superbubble are uncertain, as are their spatial correlation to the features of interstellar matter in this complex field. This makes the study of the topology and energetics of the Cygnus superbubble difficult. This study is focused on the massive stellar content of Cygnus star-forming field with purpose to provide new insights on its structure. We have gathered from the literature all available photometric uvbybeta data for the massive stars in Cygnus. The intermediate-band uvbybeta photometry, which is our main method of investigation, allows the derivation of stellar physical parameters, such as brightness and temperature, with high precision. Knowing these parameters allow us to estimate stellar distance for all stars in our sample, map the structure of the Cygnus field, and provide homogeneous distance and age estimates to the OB-associations.