CAOSP abstracts, Volume: 38, No.: 2, year: 2008

Abstract: It is still a matter for some debate whether the group of λ Bootis stars has been homogeneously defined. A widely discussed working hypothesis postulates that two solar-abundant stars of an undetected spectroscopic binary system would mimic a single, metal-weak spectrum, thus preventing any reliable analysis of the group characteristics. Using the newest available stellar-atmosphere models and synthesis codes, we investigate whether the proposed spectroscopic-binary model can explain both the observed abundance patterns and the photometric metallicity indices, and what would be the percentage of undetected spectroscopic binary systems.