In some stellar models, particularly for evolved → massive stars,
such as → red supergiants,
→ Luminous Blue Variables, and
→ Wolf-Rayet stars,
an outermost layer of the stellar envelope where the luminosity might
exceed the → Eddington limit.
This is due to the → opacity peak
produced by the variation in the ionization level of hydrogen
in the outer → convective envelope,
beneath the surface, of very luminous stars.
The opacity peak generates supra-Eddington layers and density inversion.
The high opacity decreases the Eddington luminosity in these layers, possibly to
fainter levels than the actual stellar luminosity. As a result, the
→ radiative acceleration exceeds the
→ gravitational acceleration leading to
→ mass loss enhancement
(see, e.g., A. Maeder, Physics, Formation and Evolution of Rotating Stars,
Springer, 2009).
See also: → supra-; → Eddington limit;
→ layer.
