Interaction and ablation of fall-back disks in isolated neutron stars

TL;DR

This paper models the ablation processes and interactions of fall-back disks around neutron stars, deriving expressions for disk properties and pulsar torque effects, and discusses their observational implications.

Contribution

It introduces a new analysis of ablation rates and torque interactions for fall-back disks around neutron stars, providing formulas linking disk parameters and pulsar behavior.

Findings

Ablation rate formulas for fall-back disks are derived.

Expressions for pulsar torque components due to disk interaction are obtained.

Disk interactions may cause small pulse shape and spin-down variations, but unlikely periodic changes.

Abstract

An analysis of ablation processes is made for a fall-back disk with inner and outer radii external to the neutron-star light cylinder. The calculated ablation rate leads, with certain other assumptions, to a simple expression relating the inner radius and mean mass per unit area of any long-lived fall-back disk. Expressions for the torque components generated by interaction with the pulsar wind are obtained. It is not impossible that these could be responsible for small observable variations in pulse shape and spin-down rate but they are unlikely to be the source of the periodic changes seen in several pulsars.