The Detectability of Binary Star Planetary and Brown Dwarf Companions From Eclipse Timing Variations

TL;DR

This study assesses the detectability of binary star, planetary, and brown dwarf companions through eclipse timing variations using Kepler data, highlighting key factors influencing detection success and implications for the brown dwarf desert.

Contribution

The paper introduces a simulation-based method leveraging Kepler data to predict the detectability of third bodies around eclipsing binaries, informing future search strategies.

Findings

Orbital eccentricity and binary period are crucial for detection.

Brightness influences the likelihood of detecting companions.

Detectable companion masses and periods can be estimated with simple equations.

Abstract

In this paper, we determine the detectability of eclipsing binary star companions from eclipse timing variations using the Kepler mission dataset. Extensive and precise stellar time-series photometry from space-based missions enable searches for binary star companions. However, due to the large datasets and computational resources involved, these searches would benefit from guidance from detection simulations. Our simulations start with and benefit from the use of empirical Kepler mission data, into which we inject third bodies to predict the resulting timing of binary star eclipses. We find that the orbital eccentricity of the third body and the orbital period of the host binary star are the key factors in detecting companions. Target brightness is also likely to be a factor in detecting companions. Detectable third body masses and periods can be efficiently bound using just two equations. Our results enable the setting of realistic expectations when planning searches for eclipsing binary star planetary and brown dwarf companions. Our results also suggest the brown dwarf desert is real rather than observational selection.