Pulsations and outbursts in Be stars: Small differences - big impacts
  New high-cadence observations with BRITE covering many months confirm that coupled pairs of nonradial pulsation modes are widespread among early-type Be stars. With the difference frequency between the parental variations they may form a roughly sinusoidal variability or the amplitude may cyclicly vary. A first - amplified - beat pattern is also found. In all three cases the amplitudes of difference frequencies can exceed the amplitude sum of the base frequencies, and modulations of the star-to-circumstellar-disk mass-transfer rate may be associated with these slow variations. This suggests more strongly than any earlier observations that significant dissipation of pulsational energy in the atmosphere may be a cause of mass ejections from Be stars. A unifying interpretative concept is presented. 
D. Baade, Th. Rivinius, A. Pigulski, A. Carciofi, G. Handler, R.   Kuschnig, Ch. Martayan, A. Mehner, A.F.J. Moffat, H. Pabl...
astro-ph.SR