About ten stars orbit eclipsing binary XZ And

TL;DR

This paper uses a new analysis method to detect at least ten wide orbit stars influencing the eclipsing binary XZ Andromedae over 127 years, revealing complex orbital interactions.

Contribution

It introduces the Discrete Chi-square method (DCM) for analyzing eclipse timing variations and applies it to identify multiple wide orbit stars in XZ And.

Findings

Detected at least ten wide orbit stars with periods between 1.6 and 91.7 years.

Confirmed no eclipse changes in 127 years, suggesting coplanar orbits.

Provided instructions for applying DCM to other eclipsing binaries.

Abstract

A third body in an eclipsing binary system causes regular periodic changes in the observed (O) minus the computed (C) eclipse epochs. Fourth bodies are rarely detected from the O-C data. We apply the new Discrete Chi-square method (DCM) to the O-C data of the eclipsing binary XZ Andromedae. These data contain the periodic signatures of at least ten wide orbit stars (WOSs). Their orbital periods are between 1.6 and 91.7 years. since no changes have been observed in the eclipses of XZ And during the past 127 years, the orbits of all these WOSs are most probably co-planar. We give detailed instructions of how the professional and the amateur astronomers can easily repeat all stages of our DCM analysis with an ordinary PC, as well as apply this method to O-C data of other eclipsing binaries.