English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Context: State of the art quantitative spectroscopy of OB-stars comparessynthetic spectra (calculated by means of 1D, spherically symmetric computercodes) with observations. Certain stellar atmospheres, however, show strongdeviations from spherical symmetry, and need to be treated in 3D. Aims: Wepresent a newly developed 3D radiative transfer code, tailored to the solutionof the radiation field in rapidly expanding stellar atmospheres. We apply ourcode to the continuum transfer in wind-ablation models, and to the UV resonanceline formation in magnetic winds. Methods: We have used a 3D finite-volumemethod for the solution of the equation of radiative transfer, to studycontinuum- and line-scattering problems. Convergence has been accelerated by anon-local approximate Lambda-iteration scheme. Particular emphasis has been puton careful (spherically symmetric) test cases. Results: Typical errors of thesource functions, when compared to 1D solutions, are of the order of 10-20 %,and increase for optically thick continua. In circumstellar discs, theradiation temperatures in the (optically thin) transition region from wind todisc are quite similar to corresponding values in the wind. For MHD simulationsof dynamical magnetospheres, the line profiles, calculated with our 3D code,agree well with previous solutions using a 3D-SEI method. When compared withprofiles resulting from the `analytic dynamical magnetosphere' (ADM) model,significant differences become apparent. Conclusions: Due to similar radiationtemperatures in the wind and the transition region to the disc, the sameline-strength distribution can be applied within radiation hydrodynamiccalculations for circumstellar discs in `accreting high-mass stars'. Toproperly describe the UV line formation in dynamical magnetospheres, the ADMmodel needs to be further developed, at least in a large part of the outerwind.

3D radiative transfer: Continuum and line scattering in non-spherical winds from OB stars