A photometric and spectroscopic study of eight semi-detached eclipsing binaries

TL;DR

This study combines photometric and spectroscopic data to analyze eight semi-detached eclipsing binaries, revealing their evolutionary states, orbital variations, and potential third bodies, advancing understanding of binary star evolution.

Contribution

It provides the first detailed absolute parameter determination and orbital variation analysis for these eight semi-detached binaries, highlighting their evolutionary origins and possible third companions.

Findings

Seven systems have primary stars on the main sequence.

Secondary stars are in evolved stages, indicating past mass ratio reversal.

Two systems show secular cyclical orbital period changes.

Abstract

By cross-matching the eclipsing binary catalog from TESS with that from LAMOST MRS, semi-detached eclipsing binaries with radial velocities coverage spanning more than 0.3 phases were authenticated. The absolute parameters for these systems were determined by simultaneous modeling of light curves and radial velocities using the Wilson-Devinney program. Additionally, the secular orbital variations were further analyzed using O-C curves. Eight semi-detached eclipsing binaries have been identified. Among them, seven feature primary stars situated within the main-sequence band, while their secondaries are all in evolved stages. This suggests that these systems likely originated as detached binaries and have undergone a reversal of the mass ratio. However, TIC 428257299 is an exception where the primary is Roche lobe-filling, and its secondary has experienced mass loss events. Additionally, TIC 8677671 and TIC 318217844 demonstrate secular cyclical changes of orbital periods. Specifically, for TIC 8677671, the cyclical change could result from magnetic activity or a third body which is likely to be compact, with a mass of at least 2.97 M$_{\odot}$.