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Related papers: Non-LTE Equivalent Widths for NII with Error Estim…

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We perform non-LTE calculations of lithium in late-type stars for a wide range of stellar parameters, including quantum mechanical cross-sections for collisions with neutral hydrogen and the negative hydrogen ion. Non-LTE abundance…

Solar and Stellar Astrophysics · Physics 2015-05-13 K. Lind , M. Asplund , P. S. Barklem

We constructed a comprehensive model atom for NeI -- NeII using the most up-to-date atomic data available and evaluated the non-local thermodynamic equilibrium (NLTE) line formation for NeI and NeII in classical 1D models representing the…

Solar and Stellar Astrophysics · Physics 2020-06-24 Sofya Alexeeva , Tianxiang Chen , Tatyana Ryabchikova , Weibin Shi , Kozo Sadakane , Masayoshi Nishimura , Gang Zhao

We construct a comprehensive model atom for TiI-II using more than 3600 measured and predicted energy levels of TiI and 1800 energy levels of TiII, and quantum mechanical photoionisation cross-sections. Non-local thermodynamical equilibrium…

Solar and Stellar Astrophysics · Physics 2016-07-27 T. M. Sitnova , L. I. Mashonkina , T. A. Ryabchikova

Neutral sodium is a minority species in the atmospheres of late-type stars, and line formation in local thermodynamic equilibrium (LTE) is often a poor assumption, in particular for strong lines. We present an extensive grid of non-LTE…

Solar and Stellar Astrophysics · Physics 2015-05-27 K. Lind , M. Asplund , P. S. Barklem , A. K. Belyaev

Non-local thermodynamical equilibrium (non-LTE) line formation for neutral and singly-ionized iron is considered through a range of spectral types when the effective temperature varies from 6500 K up to 8500 K, the gravity from log g = 4…

Solar and Stellar Astrophysics · Physics 2011-04-25 L. Mashonkina

We investigated the reliability of our silicon atomic model and the influence of non-local thermodynamical equilibrium (NLTE) on the formation of neutral silicon (Si I) lines in the near-infrared (near-IR) H-band. We derived the…

Solar and Stellar Astrophysics · Physics 2016-10-20 Junbo Zhang , Jianrong Shi , Kaike Pan , Carlos Allende Prieto , Chao Liu

We present non-local thermodynamic equilibrium (NLTE) line formation calculations for Ca I and Ca II in B-F stars. The sign and the magnitude of NLTE abundance corrections depend on line and stellar parameters. We determine calcium…

Solar and Stellar Astrophysics · Physics 2018-04-11 Tatyana Sitnova , Lyudmila Mashonkina , Tatyana Ryabchikova

A new model atom of nitrogen was developed using the energy levels of N I from laboratory measurements and also predicted in atomic structure calculations and the most up-to-date atomic data for computing radiative and collisional rates of…

Solar and Stellar Astrophysics · Physics 2024-06-18 L. I. Mashonkina , T. A. Ryabchikova

A non-LTE (NLTE) abundance analysis was carried out for three extreme helium stars (EHes): BD+10 2179, BD-9 4395, and LS IV+6 002, from their optical spectra with NLTE model atmospheres. NLTE TLUSTY model atmospheres were computed with H,…

Solar and Stellar Astrophysics · Physics 2015-05-20 Gajendra Pandey , David L. Lambert

Europium plays a key role in studies of nucleosynthesis in the rapid (r-) process of neutron capture nuclear reactions and the evolution of the r-process element abundances in galaxies. We refine the method for analyzing the Eu~II lines in…

Solar and Stellar Astrophysics · Physics 2026-04-27 L. I. Mashonkina , S. A. Yakovleva

Rapidly growing datasets from stellar spectroscopic surveys are providing unprecedented opportunities to analyse the chemical evolution history of our Galaxy. However, spectral analysis requires accurate modelling of synthetic stellar…

Solar and Stellar Astrophysics · Physics 2024-03-29 J. W. E. Mallinson , K. Lind , A. M. Amarsi , K. Youakim

Aluminium plays a key role in studies of the chemical enrichment of the Galaxy and of globular clusters. However, strong deviations from LTE (non-LTE) are known to significantly affect the inferred abundances in giant and metal-poor stars.…

Solar and Stellar Astrophysics · Physics 2017-11-28 Thomas Nordlander , Karin Lind

A comprehensive model atom for Fe with more than 3000 energy levels is presented. As a test and first application of this model atom, Fe abundances are determined for the Sun and five stars with well determined stellar parameters and…

Solar and Stellar Astrophysics · Physics 2015-05-27 L. Mashonkina , T. Gehren , J. -R. Shi , A. J. Korn , F. Grupp

A comprehensive model atom was developed for Si I-II-III using the most up-to-date atomic data available so far. Based on the non-local thermodynamic equilibrium (non-LTE = NLTE) line formation for Si I, Si II, and Si III and…

Solar and Stellar Astrophysics · Physics 2020-04-08 Lyudmila Mashonkina

We report new statistical equilibrium calculations for Fe I and Fe II in the atmosphere of Late-Type stars. We used atomic models for Fe I and Fe II having respectively 256 and 190 levels, as well as 2117 and 3443 radiative transitions.…

Astrophysics · Physics 2016-08-30 F. Thevenin , T. P. Idiart

Non-local thermodynamic equilibrium (non-LTE) line formation for Ca I-Ca II, Ti I-Ti II, and Fe I-Fe II is considered in model atmospheres of giant stars with an effective temperature of 4000 K $\le$ Teff $\le$ 5000 K and a metal abundance…

Solar and Stellar Astrophysics · Physics 2016-10-05 Lyudmila Mashonkina , Tatyana Sitnova , Yuri Pakhomov

Detailed non-LTE calculations for red supergiant stars are presented to investigate the influence of NLTE on the formation of atomic iron and titanium lines in the J-band. With their enormous brightness at J-band red supergiant stars are…

Solar and Stellar Astrophysics · Physics 2015-06-04 Maria Bergemann , Rolf-Peter Kudritzki , Bertrand Plez , Ben Davies , Karin Lind , Zach Gazak

We study the formation of B I lines in a grid of cool stellar model atmospheres without the assumption of local thermodynamic equilibrium (LTE). The non-LTE modelling includes the effect of other lines blending with the B I resonance lines.…

Astrophysics · Physics 2007-05-23 Dan Kiselman , Mats Carlsson

Many promising explosion models for the elusive origin of Type Ia supernovae (SNe Ia) ultimately fail to completely reproduce a number of observed properties of these events. One limiting factor for many of these models is the use of the…

High Energy Astrophysical Phenomena · Physics 2025-05-19 Samuel J. Boos , Luc Dessart , Ken J. Shen , Dean M. Townsley

We investigate the feasibility of the Si I infrared (IR) lines as Si abundance indicators for giant stars. We find that Si abundances obtained from the Si I IR lines based on the local thermodynamic equilibrium (LTE) analysis show large…

Solar and Stellar Astrophysics · Physics 2016-05-25 Kefeng Tan , Jianrong Shi , Masahide Takada-Hidai , Yoichi Takeda , Gang Zhao
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