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D. Hartmann (Clemson University), S. Plueschke, R. Diehl (MPE, Garching), U. Oberlack (Columbia University)
Massive star winds and subsequent supernova explosions are responsible for a steady state abundance in the ISM of about one solar mass of radioactive 26Al. The decay of this isotope produces a strong gamma-ray line at 1.809 MeV. COMPTEL aboard the Compton Observatory has mapped this emission in detail. In addition to the pronounced glow in the inner Galaxy, bright emission regions are also found at large longitudes. One outstanding "hotspot" is associated with the Cygnus region. In this area several OB associations are located, and superbubble structures are well established. We study the evolution of such bubbles, driven by strong star burst epsiodes. Population synthesis methods are used to determine the energy and radiation input as a function of time, which in turn is used to calculate the hydrodynamic evolution of the expanding shell. The production of 26Al (and also 60Fe) is followed, so that we can use the observed flux at 1.809 MeV to constrain the parameters of the Cygnus bubble. COMPTEL data and superbubble simulations will be presented, and we specifically discuss the implications of gamma-ray line spectroscopy for the study of Galactic star formation.