Gas and Dust in the Circumstellar Envelopes of Stars on (and Beyond) the AGB

Paper in proceeding, 2023

Circumstellar envelopes, formed by intense winds as stars evolve along the asymptotic giant branch, have proven to be rich in different molecular species. This is an effect of different chemical processes: stellar photosphere equilibrium chemistry, non-equilibrium chemistry in the extended stellar atmosphere, and photo-induced chemistry in the outflow. Commensurate with the evolution of the gas is the formation of different microscopic solid-state particles, dust grains. The molecular setup and the grain properties depend on the characteristics and evolutionary state of the central star.