HIDES spectroscopy of bright detached eclipsing binaries from the $Kepler$ field - I. Single-lined objects

TL;DR

This study presents spectroscopic analysis of nine bright detached eclipsing binaries from the Kepler field, identifying single-lined systems, determining their orbital and physical parameters, and exploring their evolutionary status and potential additional companions.

Contribution

First detailed spectroscopic and orbital analysis of single-lined detached eclipsing binaries from Kepler, including new RV measurements and evolutionary insights.

Findings

Five single-lined binaries identified and characterized.

Outer orbit parameters derived from eclipse timing variations.

Possible detection of solar-like oscillations in RV data.

Abstract

We present results of our spectroscopic observations of nine detached eclipsing binaries (DEBs), selected from the $Kepler$ Eclipsing Binary Catalog, that only show one set of spectral lines. Radial velocities (RVs) were calculated from the high resolution spectra obtained with the HIDES instrument, attached to the 1.88-m telescope at the Okayama Astrophysical Observatory, and from the public APOGEE archive. In our sample we found five single-lined binaries, with one component dominating the spectrum. The orbital and light curve solutions were found for four of them, and compared with isochrones, in order to estimate absolute physical parameters and evolutionary status of the components. For the fifth case we only update the orbital parameters, and estimate the properties of the unseen star. Two other systems show orbital motion with a period known from the eclipse timing variations (ETVs). For these we obtained parameters of outer orbits, by translating the ETVs to RVs of the centre of mass of the eclipsing binary, and combining with the RVs of the outer star. Of the two remaining ones, one is most likely a blend of a faint background DEB with a bright foreground star, which lines we see in the spectra, and the last case is possibly a quadruple bearing a sub-stellar mass object. Where possible, we compare our results with literature, especially with results from asteroseismology. We also report possible detections of solar-like oscillations in our RVs.