2017/04/30 by Alexander P. Stephan, Smadar Naoz, B. Zuckerman
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Brown dwarf #Icy moon #Planet #Planetary surface #Sky #Solar System #Stars #Stellar, planetary, and galactic studies #White dwarf #astro-ph.SR
paper · pdf · doi:10.3847/2041-8213/aa7cf3
published as The Astrophysical Journal Letters, Volume 844, Issue 2, article id. L16, 8 pp. (2017) · 8 pages, 6 figures, published in ApJ Letters
openalex created_date 2017/05/12 · openalex publication_date 2017/07/25 · arxiv created 2017/08/24 · arxiv updated 2017/08/25 · openalex updated_date 2026/08/06
Abstract White dwarfs (WDs) have atmospheres that are expected to consist nearly entirely of hydrogen and helium, since heavier elements will sink out of sight on short timescales. However, observations have revealed atmospheric pollution by heavier elements in about a quarter to a half of all WDs. While most of the pollution can be accounted for with asteroidal or dwarf planetary material, recent observations indicate that larger planetary bodies, as well as icy and volatile material from Kuiper belt analog objects, are also viable sources of pollution. The commonly accepted pollution mechanisms, namely scattering interactions between planetary bodies orbiting the WDs, can hardly account for pollution by objects with large masses or long-period orbits. Here we report on a mechanism that naturally leads to the emergence of massive body and icy and volatile material pollution. This mechanism occurs in wide binary stellar systems, where the mass loss of the planets’ host stars during post main sequence stellar evolution can trigger the Eccentric Kozai–Lidov mechanism. This mechanism leads to large eccentricity excitations, which can bring massive and long-period objects close enough to the WDs to be accreted. We find that this mechanism readily explains and is consistent with observations.