"Explaining the winds of cool giant and supergiant stars with global 3D models"

Evolved stars and their winds play a crucial role for galactic chemical evolution, including the origin of building blocks for planets and life. Essential chemical elements, like carbon, are produced inside these stars, transported to the surface by turbulent gas flows, and ejected into interstellar space by massive outflows of gas and dust. I will present an overview of recent results and ongoing work on stellar winds. In particular, I will describe how project EXWINGS contributes to the field, creating global dynamical star-and-wind-in-a-box simulations. With such models it will be possible to follow the flow of matter, in full 3D geometry, all the way from the turbulent, pulsating interior of an asymptotic giant branch star, through its atmosphere and dust formation zone into the region where the wind is accelerated by radiation pressure on dust. Advanced instruments, which can resolve the stellar atmospheres where the winds originate, provide essential data for testing the models. I will also discuss what the recent dimming event of Betelgeuse may teach us about the still enigmatic mechanisms that drive the winds of red supergiant stars.