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Related papers: Full non-LTE spectral line formation I. Setting th…

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The double detonation is a widely discussed explosion mechanism for Type Ia supernovae, whereby a helium shell detonation ignites a secondary detonation in the carbon/oxygen core of a white dwarf. Even for modern models that invoke…

The negative hydrogen ion H$^-$ is, almost without exception, treated in local thermodynamic equilibrium (LTE) in the modelling of F, G, and K stars, where it is the dominant opacity source in the visual spectral region. This assumption…

Solar and Stellar Astrophysics · Physics 2024-09-11 Paul S. Barklem , Anish M. Amarsi

A binary neutron star merger produces a rapidly evolving transient known as a kilonova (KN), which peaks a few days after merger. Modelling of KNe has often been approached assuming local thermodynamic equilibrium (LTE) conditions in the…

High Energy Astrophysical Phenomena · Physics 2022-06-01 Quentin Pognan , Anders Jerkstrand , Jon Grumer

Creation and manipulation of non-classical states of light is rapidly becoming the focus of modern attosecond science. Here, we demonstrate numerically how interaction with such states can trigger the emergence of a many-body system with…

Quantum Physics · Physics 2026-05-15 Nikolai D. Klimkin , Misha Ivanov

The solar atmosphere is diagnosed by solving the polarized radiative transfer problem for plasmas in Non-Local Thermodynamic Equilibrium (NLTE). A key challenge in multidimensional NLTE diagnosis is to integrate efficiently the radiative…

Solar and Stellar Astrophysics · Physics 2025-03-31 E. S. Carlin , S. Blanes , F. Casas

(*** abridged ***) Context: The wings of Balmer lines are often used as effective temperature diagnostics for late-type stars under the assumption they form in local thermodynamic equilibrium. Aims: Our goal is to investigate the non-LTE…

Astrophysics · Physics 2009-11-13 P. S. Barklem

We describe a self-consistent spectrum analysis technique employing non-LTE line formation, which allows precise atmospheric parameters of massive stars to be derived: 1sigma-uncertainties as low as ~1% in effective temperature and…

Solar and Stellar Astrophysics · Physics 2015-03-17 Maria-Fernanda Nieva , Norbert Przybilla

The chemical compositions of stars encode the history of the universe and are thus fundamental for advancing our knowledge of astrophysics and cosmology. However, measurements of elemental abundances ratios, and our interpretations of them,…

Solar and Stellar Astrophysics · Physics 2024-01-02 Karin Lind , Anish Mayur Amarsi

The radiance of thermal emission, as described by Plancks law, depends only on the emissivity and temperature of a body, and increases monotonically with temperature rise at any emitted wavelength. Nonthermal radiation, such as…

Optics · Physics 2016-11-01 Assaf Manor , Matej Kurtulik , Carmel Rotschild

Instantaneous heat transfer between different phases is a common assumption for modeling heat transfer in porous media, known as Local Thermal Equilibrium (LTE). This assumption may not hold in certain technical and environmental…

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

We discuss aspects of non-LTE line formation for hydrogen in early-type stars. We evaluate the effect of variations in the electron-impact excitation cross sections in model atoms of differing complexity by comparison with observation.…

Astrophysics · Physics 2009-11-10 Norbert Przybilla , Keith Butler

The problem of radio wave reflection from an optically thick plane monotonous layer of magnetized plasma is considered at present work. The plasma electron density irregularities are described by spatial spectrum of an arbitrary form. The…

Plasma Physics · Physics 2009-09-25 N. A. Zabotin , A. G. Bronin

This is an overview of non-equilibrium aspects of the formation of solar continua and lines affecting the contributions by magnetic network and plage to spectrally resolved solar irradiance. After a brief summary of these contributions and…

Solar and Stellar Astrophysics · Physics 2019-12-03 Robert J. Rutten

Line-formation calculations in the Rayleigh-Jeans tail of the spectral energy distribution are complicated by an amplification of non-LTE effects. For hot stars this can make quantitative modelling of spectral lines in the near-IR…

Solar and Stellar Astrophysics · Physics 2015-03-17 Norbert Przybilla

The inversion of spectropolarimetric observations of the solar upper atmosphere is one of the most challenging goals in solar physics. If we account for all relevant ingredients of the spectral line formation process, such as the…

Solar and Stellar Astrophysics · Physics 2022-03-23 Jiri Stepan , Tanausu del Pino Aleman , Javier Trujillo Bueno

The near-IR HeI 10830A transition is a highly sensitive diagnostic for non-LTE effects in the helium atom. So far, non-LTE line-formation computations have failed to quantitatively reproduce observations of this line in the entire range of…

Astrophysics · Physics 2009-11-11 N. Przybilla

Non-equilibrium radiation is addressed theoretically by means of a stochastic lattice-gas model. We consider a resonating transmission line composed of a chain of radiation resonators, each at a local equilibrium, whose boundaries are in…

Statistical Mechanics · Physics 2022-07-05 Boris Rotstein , Eric Akkermans

Accurately known stellar lithium abundances may be used to shed light on a variety of astrophysical phenomena such as Big Bang nucleosynthesis, radial migration, ages of stars and stellar clusters, and planet engulfment events. We present a…

Solar and Stellar Astrophysics · Physics 2020-10-30 E. Wang , T. Nordlander , M. Asplund , A. M. Amarsi , K. Lind , Y. Zhou

We address the classical stellar-atmosphere problem and describe our method of numerical solution in detail. The problem consists of the solution of the radiation transfer equation under the constraints of hydrostatic, radiative and…

Astrophysics · Physics 2007-05-23 K. Werner , J. L. Deetjen , S. Dreizler , T. Nagel , T. Rauch , S. L. Schuh