Diversity in Evolutionary Status and Magnetic Activity among Solar-Type Twin Detached Eclipsing Binaries

TL;DR

This study analyzes four solar-type twin detached eclipsing binaries, revealing diverse evolutionary stages and magnetic activity levels despite similar masses, and suggests possible tertiary companions.

Contribution

It provides precise absolute parameters for these binaries and offers new observational insights into their evolutionary diversity and magnetic activity.

Findings

Significant differences in evolutionary stages among the binaries.

Higher magnetic activity observed in certain systems, including superflares.

Potential hierarchical triple system indicated in TIC 207398432.

Abstract

We present a combined photometric and spectroscopic analysis of four detached eclipsing binaries (KIC 8957954, KIC 10593759, KIC 8302455, and TIC 207398432), all of which exhibit composite G-type spectra and nearly equal mass ratios. Based on survey data and our own observations, we measured radial velocities with the broadening function method, applied the fd3 program for spectral disentangling, and modeled the light curves with the Wilson-Devinney code to determine accurate absolute parameters. The results reveal significant differences in evolutionary stages and magnetic activity despite their nearly equal masses. Both components of KIC 8957954 and KIC 8302455 are on the main sequence; KIC 10593759 has evolved to the subgiant stage; and in TIC 207398432, the secondary has entered the red giant phase. Stronger magnetic activity is observed in KIC 10593759 and TIC 207398432, characterized by rapid O'Connell Effect Ratio variations, with the latter also exhibiting multiple superflare events. In addition, the spectral characteristics of TIC 207398432 suggest that it may be part of a hierarchical triple system. This study provides precise absolute parameters for twin binaries and offers important observational evidence for understanding their evolutionary diversity, magnetic activity, and the possible presence of tertiary companions.