ELEMENTAL ABUNDANCE ANALYSES WITH DAO SPECTROGRAMS .13. THE SUPERFICIALLY NORMAL EARLY A-TYPE STARS 68-TAURI, 21-LYNCIS AND ALPHA-DRACONIS

Elemental abundances of three superficially normal, moderately sharp-lined early A stars, 68 Tau, 21 Lyn and alpha 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 similar to those of alpha Dra for the light elements. Its derived abundance anomalies increase with atomic number for the heavy elements.