ATOMIUM is an accepted ALMA large program (ALMA id: 2018.1.00659.L) aiming at studying the wind of cool O-rich evolved stars. The project will also make use of other instruments and tools such as VLT/SPHERE, VLTI/MATISSE, MERCATOR/HERMES, radiative transfer models, chemical networks, binary model.
PI: Leen Decin (KU Leuven, Belgium)
CoPI: Carl Gottlieb (Harvard-Smithsonian Center for Astrophysics, United States)
Scientific Rationale
Over 200 molecules and 15 dust species have been detected in the ISM, stellar winds, exoplanets, supernovae, active galactic nuclei etc. One of the most fundamental questions in astrophysics deals with the phase transition from simple molecules to larger gas-phase clusters and eventually dust grains. The outflows of evolved stars are the best laboratories to answer this pivotal question due to their rich chemistry and relatively simple dynamical structure. With this Large Program we aim to establish the dominant physical and chemical processes in the winds of oxygen-rich evolved stars over a range of stellar masses, pulsation behaviours, mass-loss rates, and evolutionary phases. The goal is to unravel the phase transition from gas-phase to dust species, pinpoint the chemical pathways, map the morphological structure, and study the interplay between dynamical and chemical phenomena. The legacy will be (1) the plethora of ground-breaking results in the field of evolved stars, astrochemistry, and the chemical life cycle of the ISM; and (2) a foundation to better understand astrochemical processes in a range of research fields, from proto-planetary disks to luminous infrared galaxies.
