WIND VARIABILITY OF LBV STARS

General properties of Luminous Blue Variables (LBV) have been reviewed by Lamers(1987). The LBV's are all close to the Humphreys-Davidson lu minosity upper limit. The semi periods of the photometric microvariati ons with DELTAV approximately 0.1m are about twice as large as for nor mal supergiants of the same L and T(eff), and 4-20 times larger than t he fundamental mode for radial pulsations. So, it is likely due to non radial pulsations. During shell ejections, which accompanied by modera te photometric variations of DELTAV approximately 1m, L(bol) remains c onstant. This fact has been explained by the quasiperiodic variations of T(eff) and the radius of pseudo-photosphere (Lamer 1986). LBV's are less stable than normal supergiants so that any internal instability has more effect on their envelopes. The nature of these instabilities remains unknown. We have found some interesting peculiarities which ca n throw light to this problem.