Absolute dimensions of the metallic-line eclipsing binary V501 Monocerotis

We report extensive high-resolution spectroscopic observations and V-band differential photometry of the slightly eccentric 7.02-day detached eclipsing binary V501 Mon (A6m+F0), which we use to determine its absolute dimensions to high precision (0.3% for the masses and 1.8% for the radii, or better). The absolute masses, radii, and temperatures are M(A) = 1.6455 +/- 0.0043 M(Sun), R(A) = 1.888 +/- 0.029 R(Sun), and T(A) = 7510 +/- 100 K for the primary, and M(B) = 1.4588 +/- 0.0025 M(Sun), R(B) = 1.592 +/- 0.028 R(Sun), and T(B) = 7000 +/- 90 K for the secondary. Apsidal motion has been detected, to which General Relativity contributes approximately 70%. The primary star is found to be a metallic-line A star. A detailed chemical analysis of the disentangled spectra yields abundances for more than a dozen elements in each star. Based on the secondary, the system metallicity is near solar: [Fe/H] = +0.01 +/- 0.06. Lithium is detected in the secondary but not in the primary. A comparison with current stellar evolution models shows a good match to the measured properties at an age of about 1.1 Gyr.