J/A+A/667/A113ivo://CDS.VizieR/J/A+A/667/A113doi:10.26093/cds/vizier.36670113CDSPoniatowski L.G.Kee N.D.Sundqvist J.O.Driessen F.A.Moens N.,Owocki S.P.Gayley K.G.Decin L.de Koter A.Sana H.2023-09-27T10:56:34Z2022-11-21T11:54:35ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.fratomic-physicsstellar-atmospheric-opacityIn accelerating and supersonic media, the interaction of photons with spectral lines can be of ultimate importance, especially in an accelerating flow. However, fully accounting for such line forces is computationally expensive and challenging, as it involves complicated solutions of the radiative transfer problem for millions of contributing lines. This currently can only be done by specialised codes in 1-D steady-state flows. More general cases and higher dimensions require alternative approaches. We presented a comprehensive and fast method for computing the radiation line-force using tables of spectral line-strength distribution parameters, which can be applied in arbitrary (multi-D, time-dependent) simulations, including those accounting for the line-deshadowing instability, to compute the appropriate opacities. We assumed local thermodynamic equilibrium (LTE) to compute a flux-weighted line opacity from ~4 million spectral lines. We fitted the opacity computed from the line-list with an analytic result derived for an assumed distribution of the spectral line strength and found the corresponding line-distribution parameters, which we here tabulated for a range of assumed input densities {rho} in [10^-20^, 10^-10^]g/cm^3^ and temperatures T in [10^4^, 10^4.7^]K. We found that the variation of the line distribution parameters plays an essential role in setting the wind dynamics in our models. In our benchmark study, we also found a good overall agreement between the O-star mass-loss rates of our models and those derived from steady-state studies using more detailed radiative transfer. Our models reinforce that self-consistent variation of the line-distribution parameters is important for the dynamics of line-driven flows. Within a well-calibrated O-star regime, our results support the proposed methodology. In practice, utilising the provided tables, yielded a factor >100 speed-up in computational time compared to specialised 1-D model-atmosphere codes of line-driven winds, which constitutes an important step towards efficient multi-D simulations. We conclude that our method and tables are ready to be exploited in various radiation-hydrodynamic simulations where the line force is important.2022A&A...667A.113Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/667/A113CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/667/A113https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/667/A113http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/667/A113https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/667/A113https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/667/A113http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/667/A113GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/667/A113/ltetableLine strength distribution parameters and Thompson scattering mass absorption coefficientQ0Q_0_ parameterspect.line.widthdoublekappa-eThompson scattering mass absorption coefficientcm**2.g**-1phys.absorption.coeffdoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlogTTemperaturelog(K)phys.temperaturedoublelogrhoDensitylog(cm**-2)phys.columnDensitydoublealphaalpha parameterspect.line.widthdoublebarQbar Q parameterspect.line.widthdouble