Jeremy Bailey

Outbursts of the Be Star Eta Centauri

Many B stars eject material to form a decretion disk of gas around the star. The disks around these Be stars are observable through their strong emission lines, particularly at H-alpha, and through the polarization of their scattered light. What causes these stars to eject material is not understood. In some Be stars the ejection of material is in the form of outbursts. We have discovered that the bright star Eta Centauri is one of the most extremely variable examples of such objects. We will present the results of extensive polarization observations of this star over 5 years, and show how these observations can provide information on the mass ejection process and the evolution of the disk through the outburst cycle.