APOGEE/Kepler Overlap Yields Orbital Solutions for a Variety of Eclipsing Binaries

Abstract

Spectroscopic eclipsing binaries (SEBs) are fundamental benchmarks in stellar astrophysics and today are observed in breathtaking detail by missions like the Transiting Exoplanet Survey Satellite (TESS), Kepler, and Apache Point Observatory Galactic Evolution Experiment (APOGEE). We develop a methodology for simultaneous analysis of high-precision Kepler light curves and high-resolution near-infrared spectra from APOGEE and present orbital solutions and evolutionary histories for a subset of SEBs within this overlap. Radial velocities extracted from APOGEE spectra using the broadening function (BF) technique are combined with Kepler light curves and to yield binary orbital solutions. The BF approach yields more precise radial velocities than the standard cross-correlation function, which in turn yields more precise orbital parameters and enables the identification of tertiary stars. The orbital periods of these seven SEBs range from 4 to 40 days. Four of the systems (KIC 5285607, KIC 6864859, KIC 6778289, and KIC 4285087) are well-detached binaries. The remaining three systems have apparent tertiary companions, but each exhibit two eclipses along with at least one spectroscopically varying component (KIC 6449358, KIC 6131659, and KIC 6781535). Gaia distances are available for four targets which we use to estimate temperatures of both members of these SEBs. We explore evolutionary histories in H–R diagram space and estimate ages for this subset of our sample. Finally, we consider the implications for the formation pathways of close binary systems via interactions with tertiary companions. Our methodology combined with the era of big data and observation overlap opens up the possibility of discovering and analyzing large numbers of diverse SEBs, including those with high flux ratios and those in triple systems.

Final Targeting Strategy for the Sloan Digital Sky Survey IV Apache Point Observatory Galactic Evolution Experiment 2 North Survey

“…Thus, in addition to the powerful dynamical constraints obtained from binary systems (e.g., relative masses; Troup et al 2016;Price-Whelan et al 2018), the eclipses render the opportunity to break the degeneracy from dynamical measurements by better understanding the properties of the two stars. APOGEE-quality radial velocities paired with highprecision light curves permit detailed characterization of systems (e.g., Clark Cunningham et al 2019). Operating in the NIR, APOGEE spectroscopy is able to probe systems that are difficult to observe in the optical due to more favorable flux-contrast ratios at infrared wavelengths, such as stars with cool, low-mass, M dwarf secondaries (Mahadevan et al 2019, K. Hambleton & A. Prsa 2021.…”

Final Targeting Strategy for the SDSS-IV APOGEE-2N Survey

“…Thus, in addition to the powerful dynamical constraints obtained from binary systems (e.g., relative masses; Troup et al 2016;Price-Whelan et al 2018), the eclipses render the opportunity to break the degeneracy from dynamical measurements by better understanding the properties of the two stars. APOGEE-quality radial velocities paired with high precision light curves permit detailed characterization of systems (e.g., Clark Cunningham et al 2019). Operating in the NIR, APOGEE spectroscopy is able to probe systems that are difficult in the optical due to favorable flux-contrast ratios at infrared wavelengths, such as stars with cool, low-mass, M-dwarf secondaries (Mahadevan et al 2019, K. Hambleton & A. Prsa in prep.).…”

Comparative Study of TESS Photometry and Radial Velocities on Six Early K-type Contact Binaries with Similar Periods around 0.268 Day

“…Jayasinghe et al (2020) combined APOGEE with other databases to study CBs. Clark Cunningham et al (2019) used APOGEE spectra to measure RVs of close binaries with long periods, which they applied a broadening function technique (Rucinski 2002) to accomplish. By utilizing the APOGEE spectra together with the highprecision space TESS photometric data, it is hoped that joint studies can be made of K-type CBs that provide evidence for the A/W-subtype problem.…”