Abundances from disentangled component spectra: theeclipsing binary V578 Mon

Chemical abundances of the early B type components of the binary V578 Mon are derived from disentangled component spectra. This is a pilot study showing that, even with moderately high line-broadening, metal abundances can be derived from disentangled spectra with a precision of 0.1 dex, differential to sharp-lined single stars of the same spectral type. This binary is well-suited to such an assessment because of its youth as a member of the Rosette Nebula cluster NGC 2244, strengthening the expectation of an unevolved ZAMS chemical composition. The method is useful for studying rotationally driven mixing in main-sequence stars, since fundamental stellar parameters are known with higher accuracy in (eclipsing) binaries. This paper also evaluates of the bias that might be present in disentangled spectra.