An N band interferometric survey of the disks around post-AGB binary stars

TL;DR

This paper presents the first mid-infrared interferometric survey of post-AGB binary stars, revealing that their circumstellar dust is primarily contained in stable, continuous circumbinary disks, confirmed through spatially resolved observations and modeling.

Contribution

It provides the first mid-IR interferometric data on post-AGB binaries, demonstrating the prevalence of stable, continuous circumbinary disks in these systems.

Findings

Most systems have compact, continuous disks from sublimation radius outward.

The dust structures are spatially resolved and consistent with radiative transfer models.

The survey confirms the disk origin of IR excess in post-AGB binaries.

Abstract

It is now well established that FGK post-AGB stars that are surrounded by both hot and cold dust (as derived from the spectral energy distribution), are almost always part of a binary system with $100 < P_{orb} < 5000$~days. The properties and long-term stability of the dust emission requires it to arise from a gas- and dust-rich, puffed-up and (semi-)stable circumbinary disk. This interpretation has been confirmed with spatially resolved observations at a range of wavelengths for various individual objects. Here I present the first results of the first mid-IR interferometric survey of this class of objects. Our sample comprises 18 sources, most of which are confirmed binaries and which cover a range in IR excess. Our analysis clearly shows the compactness of the dust structures in these systems. We perform a statistical comparison with radiative transfer disk models, showing that most objects are indeed continuous disks from the sublimation radius outwards.