The great escape: how exoplanets and smaller bodies desert dying stars

Abstract

Mounting discoveries of extrasolar planets orbiting post-main-sequence stars motivate studies to understand the fate of these planets. In the traditional 'adiabatic' approximation, a secondary's eccentricity remains constant during stellar mass-loss. Here, we remove this approximation, investigate the full two-body point-mass problem with isotropic mass-loss, and illustrate the resulting dynamical evolution. The magnitude and duration of a star's mass-loss combined with a secondary's initial orbital characteristics might provoke ejection, modest eccentricity pumping, or even circularization of the orbit. We conclude that Oort Clouds and wide-separation planets may be dynamically ejected from 1-7 M☉ parent stars during AGB evolution. The vast majority of planetary material that survives a supernova from a 7-20 M☉ progenitor will be dynamically ejected from the system, placing limits on the existence of first-generation pulsar planets. Planets around >20 M☉ black hole progenitors may easily survive or readily be ejected depending on the core collapse and superwind models applied. Material ejected during stellar evolution might contribute significantly to the free-floating planetary population.