The Long-Term H$\alpha$ Emission Line Variation in $\alpha$ Eri
  The long-term variation of the H$\alpha$ line in $\alpha$ Eri has 14-15 years cyclic \bbe phase transitions. The disc formation time scales, interpreted as the periods during which the H$\alpha$ line emission increases from zero to its maximum, agree with the viscous decretion model. On the other hand, the time required for the disc dissipation ranges from 6 to 12 years which questions the viscous disc model predictions. 
M.M.F. Vinicius (IAGCAUSP), Nelson Vani Leister (IAGCAUSP), Juan Zorec   (IAP), Ronaldo Levenhagen (IAGCAUSP)