2006MNRAS.370..819I

The main goal of this paper is to continue a systematic abundance analysis of a sample of Am binaries in order to search for possible abundance anomalies driven by tidal interaction in these binary systems.

New CCD observations in two spectral regions (6400-6500 and 6660-6760 Å) of HD861, HD18778, HD20320, HD29479, HD96528 and HD108651 were obtained. Synthetic spectrum analysis was carried out, and basic stellar properties, effective temperatures, gravities, projected rotational velocities, masses, ages and abundances of several elements were determined. We conclude that HD861, 29479 and 108651 are typical Am stars, while HD20320 and 96528 are mild Am stars. HD18778 turned out not to be an Am star although its projected rotational velocity is very low (27 km.s^–1). On the contrary, HD96528 has one of the highest projected rotational velocities (85 km.s^–1) among Am binaries with orbital periods in the range 20-200 d, and yet it exhibits Am anomalies. Pseudo-synchronization and abundance anomalies are discussed in the context of possible tidal effects.