The Great Escape III: Placing post-main-sequence evolution of planetary
  and binary systems in a Galactic context
  Our improving understanding of the life cycle of planetary systems prompts
investigations of the role of the Galactic environment before, during and after
Asymptotic Giant Branch (AGB) stellar evolution. Here, we investigate the
interplay between stellar mass loss, Galactic tidal perturbations, and stellar
flybys for evolving stars which host one planet, smaller body or stellar binary
companion and reside in the Milky Way's bulge or disc. We find that the
potential evolutionary pathways from a main sequence (MS) to a white dwarf (WD)
planetary system are a strong function of Galactocentric distance only with
respect to the prevalence of stellar flybys. Planetary ejection and collision
with the parent star should be more common towards the bulge. At a given
location anywhere in the Galaxy, if the mass loss is adiabatic, then the
secondary is likely to avoid close flybys during AGB evolution, and cannot
eventually escape the resulting WD because of Galactic tides alone. Partly
because AGB mass loss will shrink a planetary system's Hill ellipsoid axes by
about 20 to 40 per cent, Oort clouds orbiting WDs are likely to be more
depleted and dynamically excited than on the MS.
