2021ApJ...921....5B

Evidence of rotational light modulation in 30%-40% of normal B stars is presented, suggesting the presence of starspots and photospheric activity. On this basis, we propose that mass loss in Be stars is a result of magnetic reconnection coupled with rapid but not necessarily near-critical rotation. The ejected matter is trapped at two diametrically opposed locations where the magnetic and geometric equators intersect. Nonradial pulsation plays no role in the mass loss and in the short-period light and line profile variations, though Be stars may pulsate as SPB or β Cep variables. The model allows many of the major characteristics of Be stars to be understood, including the frequency pattern in the periodogram, allowing the approximate rotational frequency to be identified. From a large number of Be stars observed by TESS, it is shown that the resulting equatorial rotational velocities, v, are consistent with the projected rotational velocities, vsini. Furthermore, it is shown that Be stars are rotating in a broad range of 30%-100% of the critical rotational velocity. This agrees with several statistical vsini analyses, which all show that Be stars are very unlikely to be rotating at near-critical velocities.