Fundamental parameters for dEB SB2 binary system J064726.39+223431.6

TL;DR

This study characterizes the fundamental parameters of the eclipsing binary system J064726.39+223431.6 using spectroscopic and photometric data, revealing discrepancies with theoretical models and providing insights into stellar evolution.

Contribution

First detailed parameter determination of the binary system J064726.39+223431.6 combining spectra and TESS photometry, highlighting model discrepancies.

Findings

Measured stellar masses and radii with high precision.

Identified inconsistency between observed properties and theoretical models.

Estimated system age of 1.56 Gyr, younger than Sun.

Abstract

We present a study of eclipsing binary J064726.39+223431.6 using spectra from the LAMOST-MRS and TESS photometry. We use full-spectrum fitting to derive radial velocities and spectral parameters: ${T_{\rm eff}}_{A,B}=6177,\,5820$ K, $v \sin{i}_{A,B}=59,\,50~\kms$ and ${\rm [Fe/H]}_{A,B}=-0.19$ dex. The orbital solution and light curve analysis suggest that it is a close pair of fast rotating stars on circular orbit. We measure their masses to be $M_{A,B}=1.307\pm0.007,\, 1.129\pm0.005\,M_\odot$ and their radii to be $R_{A,B}=1.405\pm0.052,\, 1.219\pm0.060\,R_\odot$ resulting in surface gravities of $\log{g}_{A,B}=4.259\pm0.033,\,4.319\pm0.042$ (cgs). Theoretical models cannot match all of these properties, predicting significantly higher ${T_{\rm eff}}$ for a given metallicity. Derived age of the system 1.56 Gyr indicates that both components are younger than Sun, which contradicts to much longer orbit's circularisation timescale.