Partial disruption of a planet around a white dwarf: the effect of perturbation from the remnant planet on the accretion

TL;DR

This paper investigates how gravitational perturbations from a remnant planet influence the partial disruption of an inner planet around a white dwarf, contributing to the understanding of pollution in white dwarf atmospheres.

Contribution

It introduces a detailed model of a triple system with a white dwarf and two planets, exploring how perturbations affect partial planetary disruption and accretion processes.

Findings

Perturbations from the remnant planet facilitate fragment accretion onto the white dwarf.

Mass loss rate depends on planetary internal structure and orbital configuration.

Partial disruption occurs periodically, influencing pollution levels in white dwarf atmospheres.

Abstract

About 25\% -50\% of white dwarfs (WDs) are found to be polluted by heavy elements. It has been argued that the pollution could be caused by the tidal disruption of an approaching planet around the WD, during which a large number of clumps would be produced and would finally fall onto the WD. The reason that the planet approaches the WD is usually believed to be due to gravitational perturbations from another distant planet or stellar companion. However, the dynamics of the perturbation and the detailed partial disruption process are still poorly understood. In this study, we present an in-depth investigation of these issues. A triple system composed of a WD, an inner orbit planet, and an outer orbit planet is considered. The inner plant would be partially disrupted periodically in the long-term evolution. Fragments generated in the process are affected by the gravitational perturbations from the remnant planet, facilitating their falling toward the WD. The mass loss rate of the inner planet depends on both its internal structure and also on the orbital configuration of the planetary system.