The core-wing anomaly of cool Ap stars - Abnormal Balmer profiles

The profiles of H alpha in a number of cool Ap stars are anomalous. Broad wings, indicative of temperatures in the range 7000-8000 K end abruptly in narrow cores. The widths of these cores are compatible with those of dwarfs with temperatures of 6000 K or lower. This profile has been known for Przybylski's star, but it is: seen in other cool Ap stars. The H beta profile in several of these stars shows a similar core-wing anomaly (CWA). In Przybylski's star, the CWA is probably present at higher Balmer members. We are unable to account for these profiles within the context of LTE and normal dwarf atmospheres. We conclude that the atmospheres of these stars are not "normal". This is contrary to a notion that has long been held.