A systematic survey of grain growth in discs around post-AGB binaries with PACS and SPIRE photometry

TL;DR

This paper uses Herschel photometry and radiative transfer modeling to analyze grain growth in circumbinary discs around post-AGB stars, providing insights into disc evolution and dust properties.

Contribution

It extends the spectral energy distributions of post-AGB binary systems to sub-millimetre wavelengths and employs modeling to diagnose grain growth as an evolutionary indicator.

Findings

Detection of large grains in circumbinary discs.

Correlation between spectral indices and grain size.

Evidence of dust evolution in post-AGB binary systems.

Abstract

Post-AGB stars are the final stage of evolution of low-intermediate mass stars (M<8 Solar Masses). Those in binary systems have stable circumbinary discs. Using data from Herschel (PACS/SPIRE), we extend the SEDs of 50 galactic post-AGB binary systems to sub-millimetre wavelengths and use the slope of the SED as a diagnostic tool to probe the presence of large grains. Using a Monte Carlo radiative transfer code (MCMax), we create a large grid of models to quantify the observed spectral indices and use the presence of large grains in the disc as a proxy for evolution.