1997/10/15 by Martin Asplund, M. Asplund, Asplund, Martin · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #Astrophysics and Star Formation Studies #FOS: Physical sciences #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9710158
11 pages; accepted for publication in Astronomy & Astrophysics
arxiv created 1997/10/15 · openalex publication_date 1997/10/15 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Super-Eddington luminosities in hydrostatic model atmospheres manifest themselves by the presence of gas pressure inversions. Such inversions are not an artifact of the assumption of hydrostatic equilibrium but can also be present in hydrodynamical model atmospheres. Only for very large mass loss rates hardly realized in supergiants will the inversions be removed. Instabilities may, however, still be present in such inversions, which is investigated for both H-rich and H-deficient late-type supergiant model atmospheres. A local, non-adiabatic, linear stability analysis reveals that sound waves can be amplified due to the strong radiative forces. However, despite the super-Eddington luminosities, the efficiency of the radiative instabilities is fairly low compared to for early-type stars with growth rates of 10-5 s-1.