Close Binaries with Infrared Excess: Destroyers of Worlds?

TL;DR

This study uses Spitzer data to investigate infrared excesses in close binary systems, revealing dust presence and potential planetary destruction mechanisms, suggesting binaries may destabilize planetary orbits and clear dust through dynamical interactions.

Contribution

It provides new infrared observations of close binaries, models dust distribution, and discusses the impact of binary dynamics on planetary system stability.

Findings

Infrared excesses found in 3 out of 10 systems

Central dust clearing radius of 0.22 AU consistent with models

Close binaries may destabilize planetary orbits and destroy worlds

Abstract

We present the results of a Spitzer photometric investigation into the IR excesses of close binary systems. In a sample of 10 objects, excesses in IRAC and MIPS24 bands implying the presence of warm dust are found for 3. For 2 objects we do not find excesses reported in earlier IRAS studies. We discuss the results in the context of the scenario suggested by Rhee and co-workers, in which warm dust is continuously created by destructive collisions between planetary bodies. A simple numerical model for the steady-state distribution of dust in one IR excess system shows a central clearing of radius 0.22 AU caused by dynamical perturbations from the binary star. This is consistent with the size of the central clearing derived from the Spitzer spectral energy distribution. We conclude that close binaries could be efficient "destroyers of worlds", lead to destabilize the orbits of their planetary progeny by magnetically-driven angular momentum loss and secular shrinkage of the binary separation.