2019ApJ...876...41T

We report extensive differential V-band photometry and high-resolution spectroscopic observations of the early F-type, 1.06-day detached eclipsing binary V506 Oph. The observations, along with times of minimum light from the literature, are used to derive a very precise ephemeris and the physical properties for the components, with the absolute masses and radii being determined to 0.7% or better. The masses are 1.4153 ± 0.0100 M_☉ and 1.4023 ± 0.0094 M_☉ for the primary and secondary, the radii are 1.725 ± 0.010 R_☉ and 1.692 ± 0.012 R_☉, and the effective temperatures are 6840 ± 150 K and 6780 ± 110 K, respectively. The orbit is circular and the stars are rotating synchronously. The accuracy of the radii and temperatures is supported by the resulting distance estimate of 564 ± 30 pc, which is in excellent agreement with the value implied by the trigonometric parallax listed in the Gaia/Data Release 2 catalog. Current stellar evolution models from the Modules for Experiments in Stellar Astrophysics (MESA) Isochrones and Stellar Tracks series for a composition of [Fe/H] = -0.04 match the properties of both stars in V506 Oph very well at an age of 1.83 Gyr and indicate they are halfway through their core hydrogen-burning phase.