Pulsations and outbursts in Be stars: Small differences - big impacts

Pulsations and outbursts in Be stars: Small differences – big impacts

D. Baade, Th. Rivinius, A. Pigulski, A. Carciofi, G. Handler, R. Kuschnig, Ch. Martayan, A. Mehner, A. F. J. Moffat, H. Pablo, A. Popowicz, S. M. Rucinski, G. A. Wade, W. W. Weiss and K. Zwintz

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.

Proceedings of the Polish Astronomical Society, vol. 5, 196-205 (2017)

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