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_⊙, R_A = 1.888 ± 0.029 R_⊙, and $T_{eff}^A$ = 7510 ± 100 K for the primary and M_B = 1.4588 ± 0.0025 M_⊙, R_B = 1.592 ± 0.028 R_⊙, and T_eff^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.