Post-Main Sequence Evolution of Debris Discs

TL;DR

This paper develops a theoretical framework to study how stellar evolution affects debris discs, predicting their detectability around evolved stars and comparing with observations.

Contribution

It introduces a model for debris disc evolution from main sequence to white dwarf phases, extending understanding of debris discs around evolved stars.

Findings

Discs around evolved stars are harder to detect than on the main sequence.

Discs could be detectable with Herschel or Alma on the giant branch.

White dwarf debris discs are consistent with observed systems like the Helix nebula.

Abstract

The population of debris discs on the main sequence is well constrained, however very little is known about debris discs around evolved stars. In this work we provide a theoretical framework that considers the effects of stellar evolution on debris discs; firstly considering the evolution of an individual disc from the main sequence through to the white dwarf phase, then extending this to the known population of debris discs around main sequence A stars. It is found that discs around evolved stars are harder to detect than on the main sequence. In the context of our models discs should be detectable with Herschel or Alma on the giant branch, subject to the uncertain effect of sublimation on the discs. The best chances are for hot young white dwarfs, fitting nicely with the observations e.g the helix nebula (Su et al. 2007) and 9 systems presented by Chu & Bilikova.