The impact of massive stars on their surrounding interstellar medium - An observational perspective

In this paper, I present a brief overview of the observational evidence for the interaction between the winds of hot stars and their surrounding inter stellar medium (ISM). As the star evolves, it will impinge on the gas in di fferent ways depending on the nature of its wind and on the physical state of the interstellar gas. The three main evolutionary phases of massive star s, the main sequence O phase, the intermediate red supergiant, or luminous blue variable phase and finally the Wolf-Rayet phase are discussed. The stu dy of the ISM in the vicinity of hot stars is shown to be a powerful tool t o study the history of the gas and gain more insight into the evolution of the star.