Orbital period changes and the higher-order multiplicity fraction amongst SuperWASP eclipsing binaries

TL;DR

This study analyzes orbital period variations in nearly 14,000 eclipsing binaries from SuperWASP, finding evidence for third bodies in about 24% of systems, indicating a high prevalence of multiple-star systems.

Contribution

It provides the first large-scale estimate of higher-order multiplicity fraction in eclipsing binaries using SuperWASP data, highlighting the significance of third bodies in orbital period changes.

Findings

2% show sinusoidal period changes suggestive of third bodies

22% exhibit linear period changes, likely due to long-term sinusoidal variations

Estimated higher-order multiplicity fraction of 24% among SuperWASP binaries

Abstract

Orbital period changes of binary stars may be caused by the presence of a third massive body in the system. Here we have searched the archive of the Wide Angle Search for Planets (SuperWASP) project for evidence of period variations in 13927 eclipsing binary candidates. Sinusoidal period changes, strongly suggestive of third bodies, were detected in 2% of cases; however, linear period changes were observed in a further 22% of systems. We argue on distributional grounds that the majority of these apparently linear changes are likely to reflect longer-term sinusoidal period variations caused by third bodies, and thus estimate a higher-order multiplicity fraction of 24% for SuperWASP binaries, in good agreement with other recent figures for the fraction of triple systems amongst binary stars in general.