The SDSS-Het Survey of Kepler Eclipsing Binaries: Spectroscopic Dynamical Masses of the Kepler-16 Circumbinary Planet Hosts

We have used high-resolution spectroscopy to observe the Kepler-16 eclipsing binary as a double-lined system and measure precise radial velocities for both stellar components. These velocities yield a dynamical mass ratio of q = 0.2994 ± 0.0031. When combined with the inclination, i = 90 3401 +0.0016 − 0.0019 , measured from the Kepler photometric data by Doyle et al. (D11), we derive dynamical masses for the Kepler-16 components of M A = 0.654 ± 0.017 M ☉ and M B = 0.1959 ± 0.0031 M ☉ , a precision of 2.5% and 1.5%, respectively. Our results confirm at the ∼2% level the mass-ratio derived by D11 with their photometric-dynamical model (PDM), q = 0.2937 ± 0.0006. These are among the most precise spectroscopic dynamical masses ever measured for low-mass stars and provide an important direct test of the results from the PDM technique.