Impact of HI cooling and study of accretion disks in asymptotic giant branch wind-companion smoothed particle hydrodynamic simulations

High-resolution observations reveal that the outflows of evolved low- and intermediate-mass stars harbour complex morphological structures that are linked to the presence of one or multiple companions. Hydrodynamical simulations provide a way to study the impact of a companion on the shaping of the asymptotic giant branch (AGB) star out-flow. Using smoothed particle hydrodynamic (SPH) simulations of an AGB star i atomic line cooling on the flow morphology. We also study how this affects the properties of the accretion disks that form around the companion. We used the Phantom i cooling. i i i cooling, provided the accretion radius is small enough. The disks have radial sizes ranging from about 0.4 to 0.9\,au and masses around odot $. For the considered wind velocities, mass accretion onto the companion is up to a factor of 2 higher than predicted by the standard Bondi Hoyle Littleton rate, ranging between $ 4 $ to $21 <!PCT!>$ of the AGB wind mass loss rate. The lower the wind velocity at the location of the companion, the larger and the more massive the disk and the higher the mass accretion efficiency. In eccentric systems, the disk size, disk mass, and mass accretion efficiency vary, depending on the orbital phase. i cooling is an essential ingredient to properly model the medium around the companion where density-enhanced wind structures form and it favours the formation of an accretion disk.