Searching For and Monitoring Ae and A Shell Stars at the DAO

To demonstrate the continued utility of the venerable DAO 1.8-m Plaskett telescope to carry out large spectroscopic observing programs, we have obtained high S/N, moderate-resolution spectra of the Hα profile of ≈ 400 A-type stars north of δ = 20° and with v sin i>150 km s^-1. These data have been used to estimate the incidence of circumstellar shell and emission line features in rapidly rotating A stars. Hα shell or emission features are observed in more than 60 stars, or about 15% of the survey sample, and approximately 30 of these are bright, previously unreported shell or emission line stars. As has been observed for the classical Be stars, the frequency of shell or emission features in A-type stars decreases towards late-A spectral types and also with decreasing vsin{i}.