Cologne-Bonn Symposium on the habitats of massive stars across cosmic time

Massive stars shape the evolution of galaxies through their intense radiation, feedback and ultimate deaths, yet their habitats and impact vary widely across cosmic time. Understanding the life cycle of baryonic matter, the chemical enrichment of the Universe and the regulation of star formation requires two major steps: first, bridging the large dynamic range in scale from sub-parsec dense clumps where stars are born up to hundreds of kiloparsecs in the circumgalactic medium that is affected by their feedback, and second, comparing environments that range from quiescent, nearby spiral galaxies to turbulent, high-redshift starbusts. This symposium aims to unite experts in observations, theory, simulations, laboratory astrophysics and instrumentation to identify the key physical and chemical processes governing the formation and impact of massive stars in their diverse cosmic habitats. The main questions to be addressed will focus on how universal the massive star formation process is across these diverse environments, how efficient stellar feedback is in dispersing different media, and whether the processes and structures observed locally are universal across the Universe.