Astron. Astrophys. Suppl. Ser.
Volume 128, Number 3, March II 1998
|Page(s)||497 - 505|
|Published online||15 March 1998|
Lithium and metal abundances in long period Am binaries*
Astronomical Institute, Slovak Academy of Sciences, 059 60 Tatranská Lomnica, The Slovak Republic
2 Institute of Astronomy, National Astronomical Observatory, P.O.B. 136, BG-4700, Smolyan, Bulgaria
Send offprint request to: J. Budaj
High signal-to-noise CCD spectra of three bright, long period Am binaries (HD 108651, HD 116657 and HD 138213) have been obtained and the atmospheric abundances of identified chemical elements were studied. We found HD 116657 to be a new candidate as a Li deficient, long period Am binary, in addition to 16 Ori. While HD 108651 and HD 116657 have pronounced Am characteristics, HD 138213 is just a mild Am star. These stars were further studied in a more general context related to the role of binarity in CP phenomenon. It was found that both Li abundance and the equivalent with ratio Ca 6718/Fe 6679 are more peculiar in systems with more pronounced eccentricities. Such behaviour is the opposite of what was previously found in Ap binaries and their anomalies. It indicates that tidal effects are of crucial importance in driving CP phenomena.
Key words: stars: chemically peculiar / stars: abundances / stars: individual: HD 108651, HD 116657, HD 138213 / binaries: general
© European Southern Observatory (ESO), 1998