# Eclipsing Binaries

## Summary

Monitoring Kepler eclipsing binary (EB) systems.

## Finding Targets

An object whose APOGEE_TARGET1 value includes one or more of the bitmasks in the following table was targeted for spectroscopy as part of this ancillary target program. See SDSS-III bitmasks to learn how to use these values to identify objects in this ancillary target program.

APOGEE_TARGET1
bit name
Bit Target Description
APOGEE_KEPLER_EB 23 eclipsing binary system

## Description

This ancillary program is monitoring Kepler EB systems to derive their dynamical mass ratios. Although masses and radii have been measured to the ~3% level for nearly 300 EBs (e.g., DEBCat), low-mass (M < 0.8M) and longer-period (P > 5 days) systems remain under-explored. The Kepler dataset is a valuable source of EBs, providing nearly continuous, extremely high-precision photometry (Caldwell et al. 2010) that has been used to detect thousands of EBs across a wide range of stellar parameters and orbital periods (Coughlin et al. 2011; Prša et al. 2011; Slawson et al. 2011). When combined with time-series spectroscopy to measure precise RVs (e.g., Bender et al. 2012), these EBs will offer empirical constraints for next-generation stellar models. See Fleming et al. (2015) for some published results.

## Primary contacts

Penn State University
suvrath -at- astro.psu.edu
Scott Fleming
STScI
fleming -at- stsci.edu

## Other contacts

Chad Bender, Rohit Deshpande, Fred Hearty, David Nidever, Ryan Terrien

## Target Selection Details

The sample of Kepler EBs comes from the catalogs of Prša et al. (2011) and Slawson et al. (2011) and includes targets in two APOGEE fields that overlap Kepler pointings (N6791 and N6819). By design, the target selection imposed a minimum amount of selection cuts in order to explore as diverse a range of stellar and orbital properties as possible. The sample targets are limited to EBs with H < 13.0 mag (Vega) and classified as having a “detached morphology”(i.e., excluding those binaries that experience Roche lobe overflow), which minimizes the number of model parameters. In addition to the Kepler sample, 4 EBs detected using ground-based photometry (Devor et al. 2008), the well-studied EB system CV Boo (Torres et al. 2008), and the M dwarf spectroscopic binary GJ 3630 (Shkolnik et al. 2010) are included as analysis calibrators.

## REFERENCES

Bender, C. F., Mahadevan, S., Deshpande, R., et al. 2012, ApJ, 751, L31
Caldwell, D. A., Kolodziejczak, J. J., Van Cleve, J. E., et al. 2010, ApJ, 713, L92
Coughlin, J. L., López-Morales, M., Harrison, T. E., Ule, N., & Hoffman, D. I. 2011, AJ, 141, 78
Fleming, S. W. et al. 2015, AJ, 149, 143
Prša, A. et al. 2011, AJ, 141, 83
Slawson, R. W., Prša, A., Welsh, W. F., et al. 2011, AJ, 142, 160