Speaker
Description
Massive stars have significant effects on their surroundings, they do this through ionizing stellar radiation, mechanical feedback from stellar winds, and energetic supernova explosions. In these processes they shape galaxies and enrich their chemistry with metals and the building blocks for life. The stellar winds also significantly affect the stars themselves. During their relatively short life times of a few million years massive stars can lose half their original mass due to stellar winds. The exact amount of mass lost can significantly affect the evolution of the star. It is now well established that the stellar winds of hot stars scale with metallicity, however the exact dependence remains uncertain. Additionally the behavior of wind inhomogeneities or clumps, which is essential to determining the mass loss rate, as function of metallicity is unknown. I will present a new study of samples of Galactic, LMC and SMC O-type stars with metallicities of solar, half solar and a fifth solar. Scrutinizing optical and UV data to accurately determine the mass-loss rate and clumping properties in the wind. I find evidence for a stronger mass-loss dependence on metallicity for low luminosity stars than at high luminosity. As the earliest stars had lower metallicities this gives insight into the evolution and behavior of stars in the early universe.
