Tidal disruption of planetary bodies by white dwarfs II: Debris disc structure and ejected interstellar asteroids

TL;DR

This study uses advanced simulations to analyze how tidal disruptions of rocky bodies by white dwarfs create debris discs and interstellar asteroids, revealing new structural and statistical properties of these phenomena.

Contribution

It introduces a new hybrid simulation method to explore a wide range of tidal disruption scenarios, providing detailed insights into debris disc structures and ejected interstellar objects.

Findings

Disrupted larger bodies form dispersed, eccentric debris structures.

Ejected interstellar bodies follow power-law size distributions.

Results have implications for understanding peculiar stellar variability and interstellar object origins.

Abstract

We make use of a new hybrid method to simulate the long-term, multiple-orbit disc formation through tidal disruptions of rocky bodies by white dwarfs, at high-resolution and realistic semi-major axis. We perform the largest-yet suite of simulations for dwarf and terrestrial planets, spanning four orders of magnitude in mass, various pericentre distances and semi-major axes between 3 AU and 150 AU. This large phase space of tidal disruption conditions has not been accessible through the use of previous codes. We analyse the statistical and structural properties of the emerging debris discs, as well as the ejected unbound debris contributing to the population of interstellar asteroids. Unlike previous tidal disruption studies of small asteroids which form ring-like structures on the original orbit, we find that the tidal disruption of larger bodies usually forms dispersed structures of interlaced elliptic eccentric annuli on tighter orbits. We characterize the (typically power-law) size-distribution of the ejected interstellar bodies as well as their composition, rotation velocities and ejection velocities. We find them to be sensitive to the depth (impact parameter) of the tidal disruption. Finally, we briefly discuss possible implications of our results in explaining the peculiar variability of Tabby's star, the origin of the transit events of ZTF J0139+5245 and the formation of a planetary core around SDSS J1228+1040.