Visual Orbits of Spectroscopic Binaries with the CHARA Array

We present the three dimensional orbits of eight double-lined spectroscopic binaries with longer orbital periods (7–35 days) to determine the fundamental stellar parameters of each component and make critical tests of stellar evolution models. We resolve the position of the secondary stars relative to the primaries on milliarcsecond scales using fringe visibility variations in interferometric observations with the CHARA Array, and measure new radial velocities using echelle spectra from the APO 3.5m, CTIO 1.5m, and Fairborn 2.0m telescopes. By combining the visual and spectroscopic observations, we solve for the orbital parameters for these systems and derive the stellar masses and distance. We then estimate the stellar radii from the distance and the angular diameter, set by fitting spectrophotometry from the literature to binary SED models or by directly fitting the interferometric visibilities. Finally, we compare the observed stellar parameters to the predictions of Yonsei-Yale and MESA stellar evolution models in order to estimate the ages of each system. We find that our distances from orbital parallax agree with the Gaia DR2 distances from trigonometric parallax, and that the mass-luminosity relationship for our long period systems generally agrees with that of short period systems. Therefore, the short period eclipsing binaries are good tools for testing models of stellar structure and evolution designed for single stars