# Throwing Icebergs at White Dwarfs

## TL;DR

This paper proposes a new mechanism involving wide binary systems and the Eccentric Kozai-Lidov effect to explain the presence of heavy elements and icy material in white dwarf atmospheres, aligning with recent observations.

## Contribution

It introduces a novel pollution mechanism triggered by stellar evolution in binary systems, accounting for large and icy bodies polluting white dwarf atmospheres.

## Key findings

- Mechanism explains observed heavy element pollution in white dwarfs.
- Eccentric Kozai-Lidov effect causes objects to approach white dwarfs.
- Consistent with recent observational data.

## Abstract

White dwarfs 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 white dwarfs. 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 white dwarfs, 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 white dwarfs to be accreted. We find that this mechanism readily explains and is consistent with observations.