Photospheric metal abundances of AR Lacertae

High-resolution spectra of the RS CVn system AR Lac taken during total ecli pse of the primary component lead to a precise determination of the stellar effective temperature of the secondary, T-eff = 5100 +/- 100 K, and a surf ace gravity log g = 3.65 +/- 0.1. The small-scale motions are well represen ted by a microturbulence velocity of nu(t) = 1.6 +/- 0.3 km s(-1). Examinat ion of a number of spectral windows by means of spectrum synthesis based on solar spectrum reference fits produces a pattern of photospheric metal abu ndances that is essentially represented by solar or slightly enhanced value s. This is at variance with the subsolar metal abundances reported from X-r ay observations with the ROSAT and ASCA satellites. The effective temperature determined here restricts the surface fraction of cool matter such as confined in star spots during the present observations to values around 0.3. For a close binary system with an active chromospher e the photospheric spectra are normal. No spectrum variations on a half hou r time scale are detected.