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 \pm 0.0100 ~ { } M _ { \sun } and 1.4023 \pm 0.0094 ~ { } M _ { \sun } for the primary and secondary , the radii are 1.725 \pm 0.010 ~ { } R _ { \sun } and 1.692 \pm 0.012 ~ { } R _ { \sun } , and the effective temperatures 6840 \pm 150 K and 6780 \pm 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 \pm 30 pc , in excellent agreement with the value implied by the trigonometric parallax listed in the Gaia /DR2 catalog .
Current stellar evolution models from the MIST 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 .