Elemental abundance analyses with DAO spectrograms - XX. The early A stars epsilon Serpentis, 29 Vulpeculae and sigma Aquarii
Elemental abundances of the early A stars epsilon Ser, 29 Vul and sigma Aqr are derived consistently with previous studies of this series using spectrograms obtained with Reticon and CCD detectors. The derived abundances confirm that epsilon Ser is a definite Am star. 29 Vul shows evidence for a weakly operating Am star phenomenon. sigma Aqr, a hot Am star prototype, has abundances similar to those of o Peg, another class prototype.