the gravity on the equator. When approaching the critical rotation, the decretion disks are formed through which the angular momentum and significant amount of mass is lost [@Krticka2010a; @Krticka2011].

Pulsation
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The pulsational instability of very massive stars might contribute somewhat to the total mass loss rate although it is not clear what the contribution will be. Cool supergiants do indeed have winds which are initiated by pulsations, but then further support, such as radiative force on the dust grains, is needed to sustain a significant outflow.

The stability of very massive stars was analyzed and compared with metal enriched stars by [@Baraffe2001]. Mass loss was not taken into account because they assumed it to be negligible for zero-metallicity stars. A linear non-adiabatic analysis was carried out. In their analysis, they considered that the stars stabilize as soon as they evolve from the ZAMS, then one can expect decreasing mass loss rates along the main sequence. This is, pulsations do not lead to significant mass loss on the main sequence. For their calculations they used the so called [*flux-freezing convective theory*]{} that assumes that perturbation in the luminosity is only given by the radiative luminosity. However, the stability properties of 