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Related papers: Basics of the NLTE physics

200 papers

I summarize the stellar side of the cosmological lithium problem(s). Evidence from independent studies is accumulating and indicates that stars may very well be fully responsible for lowering their surface lithium from the predicted…

Solar and Stellar Astrophysics · Physics 2024-06-17 A. J. Korn

In the article it is shown that at presence of fundamental scalar fields determining the masses of the scalar charged particles the global thermodynamic equilibrium (GTE) is compatible with a process of the cosmological expansion of the…

General Physics · Physics 2014-10-10 Yurii Ignat'ev

The formation of the UV OH spectral lines has been investigated for a range of stellar parameters in the light of 3D hydrodynamical model atmospheres. The low atmospheric temperatures encountered at low metallicities compared with the…

Astrophysics · Physics 2009-11-06 M. Asplund , A. E. Garcia Perez

Relaxational effects in stellar heat transport can in many cases be significant. Relativistic Fourier-Eckart theory is inherently quasi-stationary, and cannot incorporate these effects. The effects are naturally accounted for in causal…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Megan Govender , Roy Maartens , Sunil Maharaj

The so-called full non-local thermodynamic equilibrium (FNLTE) radiative transfer problem allows us to take into account not only deviations of the radiation field from the Planckian but also deviations of the densities and velocity…

Solar and Stellar Astrophysics · Physics 2026-05-14 T. Lagache , M. Sampoorna , F. Paletou

We consider a relativistic radiating spherical star in conformally flat spacetimes. In particular we study the junction condition relating the radial pressure to the heat flux at the boundary of the star which is a nonlinear partial…

General Relativity and Quantum Cosmology · Physics 2014-12-23 G. Abebe , K. S. Govinder , S. D. Maharaj

We study the internal dynamics of an elementary quantum system placed close to a body held at a temperature different from that of the surrounding radiation. We derive general expressions for lifetime and density matrix valid for bodies of…

Quantum Physics · Physics 2015-03-20 Bruno Bellomo , Riccardo Messina , Mauro Antezza

Luminous BA-SGs allow topics ranging from NLTE physics and the evolution of massive stars to the chemical evolution of galaxies and cosmology to be addressed. A hybrid NLTE technique for the quantitative spectroscopy of BA-SGs is discussed.…

Astrophysics · Physics 2009-11-11 N. Przybilla , K. Butler , S. R. Becker , R. P. Kudritzki

We present new ultra-metal-poor (UMP) stars parameters with [Fe/H]<-4.0 based on line-by-line non-local thermodynamic equilibrium (NLTE) abundances using an up-to-date iron model atom with a new recipe for non-elastic hydrogen collision…

Solar and Stellar Astrophysics · Physics 2017-10-11 Rana Ezzeddine , Anna Frebel , Bertrand Plez

Spectral lines of helium are commonly observed on the Sun. These observations contain important informations about physical conditions and He/H abundance variations within solar outer structures. The modeling of chromospheric and coronal…

Solar and Stellar Astrophysics · Physics 2011-05-19 Pierre Gouttebroze , Nicolas Labrosse

The Euler equation has been accepted as the basic postulate of stellar physics long before the plasma physics was developed. The existence of electrical interaction between particles of interstellar plasma poses the question, how this…

Astrophysics · Physics 2007-09-11 B. V. Vasiliev

Using the technique of Pade Approximants for the correlation contributions of charged particles we are able to reproduce complex mathematical expressions by simple algebraic formulas. The Pade formulas are analytical expressions, which…

Astrophysics · Physics 2009-10-31 W. Stolzmann , T. Bloecker

'Relativistic thermodynamics' should be understood not as a generalization of a non-relativistic theory but as an application of a general thermodynamic framework, neutral as to spacetime setting and allowing arbitrary conserved quantities,…

Statistical Mechanics · Physics 2025-08-06 David Wallace

We construct hydrogen atmosphere models for strongly magnetized neutron stars in thermodynamic equilibrium, taking into account partial ionization. The presence of bound states affects the equation of state, absorption coefficients, and…

Astrophysics · Physics 2007-05-23 A. Y. Potekhin , D. Lai , G. Chabrier , W. C. G. Ho

It has been built a strict mathematical model of the thermodynamic equilibrium's establishment in the originally nonequilibrium cosmological ultrarelativistic plasma for the arbitrary accelerated Universe under the assumption that scaling…

General Relativity and Quantum Cosmology · Physics 2015-06-16 Yurii Ignatyev

We present a detailed investigation of neutron star atmospheres with low magnetic fields, $B < 10^8 -10^{10}$ G, which do not affect opacities and equation of state of the atmospheric matter. We compute the atmospheric structure, emergent…

Astrophysics · Physics 2007-05-23 V. E. Zavlin , G. G. Pavlov , Yu. A. Shibanov

Non-local Thermodynamic Equilibrium (NLTE) calculations of hot white dwarf (WD) model atmospheres are the cornerstone of modern flux calibrations for the Hubble Space Telescope (HST) and for the CALSPEC database. These theoretical spectral…

Solar and Stellar Astrophysics · Physics 2020-06-17 Ralph Bohlin , Ivan Hubeny , Thomas Rauch

We investigate the non-local thermodynamic equilibrium (NLTE) analysis for \ion{Cu}{1} lines with the updated model atom that includes quantum-mechanical rate coefficients of Cu\,$+$\,H and Cu$^+$\,$+$\,H$^-$ inelastic collisions from the…

Solar and Stellar Astrophysics · Physics 2022-08-31 Xiaodong Xu , Jianrong Shi , Xiaofeng Wang

A comprehensive model atom was constructed for C I using the most up-to-date atomic data. We evaluated non-local thermodynamical equilibrium (NLTE) line formation for neutral carbon in classical 1D models representing atmospheres of…

Solar and Stellar Astrophysics · Physics 2015-09-09 S. A. Alexeeva , L. I. Mashonkina

We investigate departures from local thermodynamic equilibrium (NLTE) in the line formation of neutral and singly ionised iron lines and their impact on spectroscopic stellar parameters. The calculations are performed for an extensive grid…

Solar and Stellar Astrophysics · Physics 2015-06-05 Karin Lind , Maria Bergemann , Martin Asplund