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

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: ${T_{\mathrm{eff}}}_{A,B}=6177,5820$ K, $v \sin{i}_{A,B}=59,\,50~\kms$ and ${[Fe/H]}_{A,B}=-0.19$ 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 $M_{A,B}=1.307\pm 0.007,1.129\pm 0.005M_{\odot }$ and their radii to be $R_{A,B}=1.405\pm 0.052,1.219\pm 0.060R_{\odot }$ resulting in surface gravities of $\log g_{A,B}=4.259\pm 0.033,4.319\pm 0.042$ (cgs). Theoretical models cannot match all of these properties, predicting significantly higher $T_{\mathrm{eff}}$ 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.

arXiv commentsubmitted to MNRAS. arXiv admin note: text overlap with arXiv:2204.10680