Radioactivities in Population Studies: 26Al and 60Fe from OB Associations

The observation of the interstellar 1.809 MeV decay-line of radioactive 26 Al by the imaging gamma-ray telescope COMPTEL have let to the conclusion, that massive stars and their subsequent core-collapse su­ pernovae are the dominant sources of the interstellar 26 Al abundance. Massive stars are known to affect the surrounding interstellar medium by their energetic stellar winds and by the emission of ionising radia­ tion. We present a population synthesis model allowing the correlated investigation of the gamma-ray emission characteristics with integrated matter, kinetic energy and extreme ultra-violet radiation emission of as­ sociations of massive stars. We study the time evolution of the various observables. In addition, we discuss systematic as well as statistical un­ certainties affecting the model. Beside uncertainties in the input stellar physics such as stellar rotation, mass loss rates or internal mixing mod­ ifications due to a unknown binary component may lead to significant uncertainties.