2008/06/27 by A. J. van Marle, S. P. Owocki, N. J. Shaviv · 46 citations
Physics and Astronomy · Social Sciences · #Astronomy and Astrophysical Research #Atmosphere (unit) #Eddington luminosity #Educational Leadership and Practices #Limit (mathematics) #Optical depth #Outflow #Photon #Radiation #Stars #Stellar atmosphere #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2008.13648.x
published in Monthly Notices of the Royal Astronomical Society 389(3), 1353-1359 (Oxford University Press) · Accepted for publication by MNRAS
arxiv created 2008/06/27 · openalex publication_date 2008/08/15 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present the results of numerical simulations of continuum-driven winds of stars that exceed the Eddington limit and compare these against predictions from earlier analytical solutions. Our models are based on the assumption that the stellar atmosphere consists of clumped matter, where the individual clumps have a much larger optical thickness than the matter between the clumps. This ‘porosity’ of the stellar atmosphere reduces the coupling between radiation and matter, since photons tend to escape through the more tenuous gas between the clumps. This allows a star that formally exceeds the Eddington limit to remain stable, yet produce a steady outflow from the region where the clumps become optically thin. We have made a parameter study of wind models for a variety of input conditions in order to explore the properties of continuum-driven winds. The results show that the numerical simulations reproduce quite closely the analytical scalings. The mass-loss rates produced in our models are much larger than can be achieved by line driving. This makes continuum driving a good mechanism to explain the large mass-loss and flow speeds of giant outbursts, as observed in η Carinae and other luminous blue variable stars. Continuum driving may also be important in population III stars, since line driving becomes ineffective at low metallicities. We also explore the effect of photon tiring and the limits it places on the wind parameters.