2012ApJ...751L..31B

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.