Statistical view of orbital circularisation with 14 000 characterised TESS eclipsing binaries

TL;DR

This study analyzes a large sample of over 14,000 TESS eclipsing binaries to understand orbital circularisation, its dependence on stellar properties, and the potential role of stellar pulsations in the process.

Contribution

It provides the first large-scale statistical analysis of orbital circularisation in intermediate-to-high mass eclipsing binaries using TESS data, including the role of pulsations.

Findings

Reduced eccentric fraction among pulsating systems

Confirmation that additional dissipation mechanisms are needed

Identification of critical periods and separations across temperature ranges

Abstract

Eclipsing binaries are crucial for understanding stellar physics, allowing detailed studies of stellar masses, radii, and orbital dynamics. Recent space missions like the Transiting Exoplanet Survey Satellite (TESS) have significantly expanded the catalogue of observed eclipsing binaries with uninterrupted time series photometry, providing an opportunity for large-scale ensemble studies. This study aims to analyse the statistical properties of circularisation in a large sample of intermediate-to-high mass eclipsing binaries observed by TESS. We explore the dependence of orbital circularisation on stellar properties and orbital parameters to improve our understanding of the physical processes affecting these systems. We further aim to assess the role of stellar pulsations in circularisation. We compiled a catalogue of O- to F-type stars to search for eclipsing binary signals in the TESS data. Using automated classification and data analysis methodologies, we arrive at a well-characterised sample of 14,573 eclipsing binaries. We investigate the statistical characteristics of the sample as a function of temperature, orbital period, and scaled orbital separation. The orbital circularisation was measured with statistical methods to obtain three distinct measurements of the critical period and separation in four temperature ranges. Pulsations were identified in the g- and p-mode regimes and a reduced fraction of eccentric systems was found among them. Our analysis confirmed and expanded upon previous findings that additional dissipation is needed as compared to the predictions of turbulent viscosity and non-resonant radiative damping. We speculate that pulsations may play a role in the circularisation of close binaries. Our study highlights the need for dissipative mechanisms that can produce a wide range of critical periods from a range of initial conditions.