Elemental abundance analysis with DAO spectrograms. XIII. The superficially normal early A-type stars 68 Tauri, 21 Lyncis and Alpha Draconis

Abstract

Elemental abundances of three superficially normal, moderately sharp-lined early A stars, 68 Tau, 21 Lyn and α Dra, are derived consistently with previous studies of this series, using co-added photographic spectrograms supplemented by Reticon exposures. The first two stars are hot Am stars, while the third is slightly metal-poor. 68 Tau is relatively metal-rich compared to the Sun, with its abundance anomalies tending to increase with atomic number. The abundances of 21 Lyn are sintilar to those of α Dra for the light elements. Its derived abundance anomalies increase with atomic number for the heavy elements.