Spectral Line Variability in Be and Bn Stars

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The spectral absorption lines of hot, rapidly rotating "B" type stars show traveling "bumps" which travel across the lines with time. Although these bumps were first thought to move periodically in a predictable way, leading to an interpretation that traveling waves (nonradial pulsations) were responsible, new data indicate that the bumps are often missing. In order to judge whether this apparent unpredictability is caused by the "beating" of different pulsation modes or by an aperiodic phenomenon, long strings of spectroscopic data are needed. In the past long "campaigns" have been difficult to undertake because of practical scheduling and allocation problems at national facilities. In early 1992 Georgia State will put into operation its new spectroscopic "Multi- Telescope Telescope. This facility will have a large effective light gathering power and a Charged-Couple Device detector and will permit the PI to obtain large amounts of data to examine the frequency of the "profile bump" phenomenon in rapidly rotating B stars and to ascertain its periodic nature. The PI also believes that the large database assembled will enable him to determine whether nonradial pulsations are responsible for episodic mass loss in the enigmatic group of rapidly rotating "Be" stars.