On the detectability of Bp-type abundance anomalies in early main-sequence stars.

Summary. With model atmosphere techniques, we calculate selected spectral features in near-main-sequence stars in the range from 0 9 to B 5 using anomalous element abundances which are typically found in middle to late Bp type stars. We discuss whether these abundance anomalies can be detected at classification dispersion in stars earlier than about B 3. The observed absence of weak-helium-line stars of the Si- and the -type implies the absence of anomalies of these groups in early B stars. Anomalies typical of weakhelium-line stars of the Ti-Sr-type and of manganese stars may escape detection in classification work. Key words: Ap stars Bp stars abundance anomalies