Hunt for extremely eccentric eclipsing binaries

TL;DR

This paper presents the first detailed analysis of 27 highly eccentric eclipsing binary systems, exploring their physical parameters and eccentricity distribution to test tidal circularisation theories and the influence of third bodies.

Contribution

It provides the first comprehensive analysis of high-eccentricity eclipsing binaries, including physical parameters and implications for tidal theories and third-body effects.

Findings

Eccentricities reach up to 0.8 in some systems.

Constructed period-eccentricity diagram for the sample.

Detected third-light contributions indicating possible Kozai-Lidov cycles.

Abstract

We report the very first analysis of 27 eclipsing binary systems with high eccentricities that sometimes reach up to 0.8. The orbital periods for these systems range from 1.4 to 37 days, and the median of the sample is 10.3 days. Star CzeV3392 (= UCAC4 623 022784), for example, currently is the eclipsing system with the highest eccentricity (e = 0.22) of stars with a period shorter than 1.5 days. We analysed the light curves of all 27 systems and obtained the physical parameters of both components, such as relative radii, inclinations, or relative luminosities. The most important parameters appear to be the derived periods and eccentricities. They allow constructing the period-eccentricity diagram. This eccentricity distribution is used to study the tidal circularisation theories. Many systems have detected third-light contributions, which means that the Kozai-Lidov cycles might also be responsible for the high eccentricities in some of the binaries.