Rapid destruction of planetary debris around white dwarfs through aeolian erosion

TL;DR

This paper investigates how aeolian erosion rapidly destroys small planetary debris in white dwarf systems, highlighting its dominance over other processes and its role in WD pollution.

Contribution

It introduces aeolian erosion as a key process in WD debris disk evolution, showing its importance compared to collisional and thermal destruction mechanisms.

Findings

Solid bodies smaller than ~5 km are eroded within disk lifetime.

Aeolian erosion dominates for objects less than 10^3 cm radius near the WD.

Erosion links large fragment collisions to small particle sublimation and accretion onto WDs.

Abstract

The discovery of numerous debris disks around white dwarfs (WDs), gave rise to extensive study of such disks and their role in polluting WDs, but the formation and evolution of these disks is not yet well understood. Here we study the role of aeolian (wind) erosion in the evolution of solids in WD debris disks. Aeolian erosion is a destructive process that plays a key role in shaping the properties and size-distribution of planetesimals, boulders and pebbles in gaseous protoplanetary disks. Our analysis of aeolian erosion in WD debris disks shows it can also play an important role in these environments. We study the effects of aeolian erosion under different conditions of the disk, and its erosive effect on planetesimals and boulders of different sizes. We find that solid bodies smaller than $\sim 5 \rm{km}$ will be eroded within the short disk lifetime. We compare the role of aeolian erosion in respect to other destructive processes such as collisional fragmentation and thermal ablation. We find that aeolian erosion is the dominant destructive process for objects with radius $\lesssim 10^3 \rm{cm}$ and at distances $\lesssim 0.6 R_\odot$ from the WD. Thereby, aeolian erosion constitutes the main destructive pathway linking fragmentational collisions operating on large objects with sublimation of the smallest objects and Poynting-Robertson drag, which leads to the accretion of the smallest particles onto the photosphere of WDs, and the production of polluted WDs.