Spectral History Of The Bright Be Star Omicron Aquarii

Be stars are a large group of emission-line objects that contain fast-rotating stars of B spectral type. They are surrounded by purely gaseous disk-like circumstellar envelopes, which may unexpectedly disappear and form again with a different amount of matter. The current explanation of the envelope formation involves a combination of fast rotation and non-radial pulsations, however, there is growing evidence that many Be stars are the brighter primary components of binary systems, whose secondaries are typically a few magnitudes fainter and thus evade detection. We present a spectroscopic study of the Be star Omicron Aquarii, which has demonstrated a very stable emission-line spectrum for the last 50 years. With data taken at the Three College Observatory operated by the University of North Carolina Greensboro, we find hints of periodic long- and short-term variations of the Hα line profile. In particular, the existence of a stable 72-day period in the intensity variations of the double-peaked profile may indicate the presence of an undetected secondary companion.