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 Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

As one of the most important elements in astronomy, iron abundancedeterminations need to be as accurate as possible. We investigate the accuracyof spectroscopic iron abundance analyses using archetypal metal-poor stars. Weperform detailed 3D non-LTE radiative transfer calculations based on 3Dhydrodynamic Stagger model atmospheres, and employ a new model atom thatincludes new quantum-mechanical neutral hydrogen collisional rate coefficients.With the exception of the red giant HD122563, we find that the 3D non-LTEmodels achieve Fe i/Fe ii excitation and ionization balance as well as nothaving any trends with equivalent width to within modelling uncertainties of0.05 dex, all without having to invoke any microturbulent broadening; forHD122563 we predict that the current best parallax-based surface gravity isover-estimated by 0.5 dex. Using a 3D non-LTE analysis, we infer ironabundances from the 3D model atmospheres that are roughly 0.1 dex higher thancorresponding abundances from 1D MARCS model atmospheres; these differences goin the same direction as the non-LTE effects themselves. We make availablegrids of departure coefficients, equivalent widths and abundance corrections,calculated on 1D MARCS model atmospheres and horizontally- andtemporally-averaged 3D Stagger model atmospheres.

Non-LTE line formation of Fe in late-type stars - III. 3D non-LTE analysis of metal-poor stars