The Fate of Exomoons in White Dwarf Planetary Systems

TL;DR

This paper investigates the fate of exomoons in white dwarf systems, revealing that they can significantly contribute to white dwarf pollution by reaching close to the star more easily than planets, potentially explaining observed pollution.

Contribution

It introduces the idea that liberated exomoons can play a crucial role in white dwarf pollution, a factor previously underexplored in planetary system evolution.

Findings

Exomoons can reach deep radial incursions towards white dwarfs more easily than planets.

Exomoons may be primary contributors to white dwarf pollution.

Moons can be progenitors of pollution in white dwarf systems.

Abstract

Roughly 1000 white dwarfs are known to be polluted with planetary material, and the progenitors of this material are typically assumed to be asteroids. The dynamical architectures which perturb asteroids into white dwarfs are still unknown, but may be crucially dependent on moons liberated from parent planets during post-main-sequence gravitational scattering. Here, we trace the fate of these exomoons, and show that they more easily achieve deep radial incursions towards the white dwarf than do scattered planets. Consequently, moons are likely to play a significant role in white dwarf pollution, and in some cases may be the progenitors of the pollution itself.