Nebulosities and jets from outbursting evolved stars

Abstract

In this PhD Thesis we study the occurrence of powerful stellar outbursts in the late phases of evolution of stars like the Sun. This is one of the most controversial topics in the field, as the extraordinary variety of shapes revealed by observations are not expected to be the result of the evolution of stars that are basically spherical all over their lives. The stellar ejecta that we study occur and develop on time-scales of years, even months. This allows us to study their evolution in real-time. A very rare opportunity in Astrophysics! To this aim, we have gathered over the years a unique collection of multi epoch images, from which we produce "movies" that reveal the expansion of the nebulae as projected in the plane of the sky. Images are complemented by spectra that measure the line-of-sight velocities, also required to build 3D models of the dynamical evolution of the outflows, a privileged information for theoretical modelling.