Long-lived planetesimal discs

TL;DR

This paper develops a unified framework to analyze the long-term survival of planetesimal discs across various astrophysical contexts, considering dynamical processes and detection methods.

Contribution

It introduces a comprehensive model characterizing planetesimal discs with four key parameters and explores constraints on their longevity and detectability.

Findings

Long-lived discs must satisfy multiple dynamical constraints.

Detection methods include radial velocity, transits, microlensing, and infrared emission.

The framework applies to dust, asteroids, and planets.

Abstract

We investigate the survival of planetesimal discs over Gyr timescales, using a unified approach that is applicable to all Keplerian discs of solid bodies -- dust grains, asteroids, planets, etc. Planetesimal discs can be characterized locally by four parameters: surface density, semi-major axis, planetesimal size and planetesimal radial velocity dispersion. Any planetesimal disc must have survived all dynamical processes, including gravitational instability, dynamical chaos, gravitational scattering, physical collisions, and radiation forces, that would lead to significant evolution over its lifetime. These processes lead to a rich set of constraints that strongly restrict the possible properties of long-lived discs. Within this framework, we also discuss the detection of planetesimal discs using radial velocity measurements, transits, microlensing, and the infrared emission from the planetesimals themselves or from dust generated by planetesimal collisions.