Confirming the Periodic Disk Outbursts of the Be Star HD 6226

Classical Be stars are rapidly rotating B stars that eject material into an equatorial gaseous disk. The disk can be observed through spectroscopy of emission lines and infrared excesses, where polarimetry or interferometry can reveal the orientation of the disk. The mechanisms that lead to stellar mass ejection are still unknown, so the discovery of periodic disk ejections is important to predict when to observe certain Be stars and also reveals that the underlying mass ejection mechanism can be periodic, which is an important clue to understand the physical mechanisms involved. Previously, the classical Be star HD 6226 was found to have a periodic disk behavior from four years of spectroscopy. Here we report on a time-series analysis of ∼20 yr of H α and H β spectroscopy and confirm the quasi-periodic behavior of the disk growth and dissipation.