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

¹ Institute of Astronomy, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
² Max Planck Institute for Astrophysics, Karl-Schwarzschild-Straße 1, 85741 Garching, Germany
³ Department of Astrophysics, IMAPP, Radboud University Nijmegen, PO Box 9010 6500 GL Nijmegen, The Netherlands
⁴ Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany

^⋆ Corresponding author; luc.ijspeert@kuleuven.be

Received: 25 April 2024
Accepted: 28 September 2024

Abstract

Context. 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.

Aims. 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.

Methods. We compiled a catalogue of O- to F-type stars to search for eclipsing binary signals in the data available from the first four years of the TESS mission. Using automated classification and data analysis methodologies, we arrive at a well-characterised sample of 14 573 eclipsing binaries. We supplement our catalogue with Gaia effective temperatures, and investigate the statistical characteristics of the sample as a function of temperature, orbital period, and scaled orbital separation.

Results. The orbital circularisation was measured with statistical methods to obtain three distinct measurements of the critical period and separation in four temperature ranges. These measurements cover a range of orbital periods and separations where both circularised and eccentric systems exist. Pulsations were identified in the g- and p-mode regimes and a reduced fraction of eccentric systems was found among them.

Conclusions. Our analysis revealed the dependence of orbital circularisation on stellar temperatures, also seen in other studies, and confirmed 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.