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Related papers: Radiative transfer in stellar atmospheres

200 papers

We present a transport equation for the incoherent propagation of radiation inside a quasi-resonant atomic gas at low temperature. The derivation is based on a generalized Bethe-Salpeter equation taking into account the motion of the atoms.…

Disordered Systems and Neural Networks · Physics 2009-04-07 Romain Pierrat , Benoit Gremaud , Dominique Delande

We consider the problem of radiative transfer in stellar atmospheres where the index of refraction departs from unity and is a function of density and temperature. We present modified Feautrier and Lambda-iteration methods to solve the…

Astrophysics · Physics 2009-11-10 P. M. Kowalski , D. Saumon

The highly convergent iterative methods developed by Trujillo Bueno and Fabiani Bendicho (1995) for radiative transfer (RT) applications are generalized to spherical symmetry with velocity fields. These RT methods are based on Jacobi,…

Astrophysics · Physics 2007-05-23 A. Asensio Ramos , J. Trujillo Bueno , J. Cernicharo

Based on high-resolution spectral observations for a sample of very metal-poor stars, we investigate how well stellar chemical abundances can be derived with available theoretical methods and computational tools.

Solar and Stellar Astrophysics · Physics 2018-08-22 Lyudmila Mashonkina , Tatyana Sitnova , Yuri Pakhomov , Tatyana Ryabchikova

In this paper we present a characteristic method for solving the transfer equation in differentially moving media in a curved spacetime. The method is completely general, but its capabilities are exploited at best in presence of symmetries,…

Astrophysics · Physics 2009-10-28 Silvia Zane , Roberto Turolla , Luciano Nobili , Myris Erna

Accurate accounting of particle number and 4-momentum in radiative transfer may be facilitated by the use of transport equations that allow transparent conversion between volume and surface integrals in both spacetime and momentum space.…

Astrophysics · Physics 2016-11-09 Christian Y. Cardall

We find the forms of the transfer equations for polarized cyclotron radiation in the atmospheres of compact stars, which are simple enough to allow practical implementation and still preserve all important physical effects. We take into…

High Energy Astrophysical Phenomena · Physics 2016-04-29 M. Garasev , E. Derishev , Vl. Kocharovsky , V. Kocharovsky

These lectures are intended to present a simple but relatively complete description of the theory needed to understand the formation of lines in non-local thermodynamical equilibrium (NLTE), without appealing to any previous knowledge…

Astrophysics · Physics 2007-05-23 Suzy Collin

Radiative heat exchange at the nanoscale presents a challenge for several areas due to its scope and nature. Here, we provide a thermokinetic description of microscale radiative energy transfer including phonon-photon coupling manifested…

Mesoscale and Nanoscale Physics · Physics 2013-03-20 Agustín Pérez-Madrid , Luciano C. Lapas , J. Miguel Rubí

The aim of this paper is to develop a mathematical framework for opto-elastography. In opto-elastography, a mechanical perturbation of the medium produces a decorrelation of optical speckle patterns due to the displacements of optical…

Mathematical Physics · Physics 2013-06-19 Habib Ammari , Emmanuel Bossy , Josselin Garnier , Wenjia Jing , Laurent Seppecher

Radiative transfer in curved spacetimes has become increasingly important to understanding high-energy astrophysical phenomena and testing general relativity in the strong field limit. The equations of radiative transfer are physically…

Astrophysics · Physics 2009-11-13 Avery E. Broderick

The determination of atmospheric parameters depends on the use of radiative transfer codes (among other elements such as model atmospheres) to compute synthetic spectra and/or derive abundances from equivalent widths. However, it is common…

A mayor problem that arises in the computation of stellar atmosphere models is the self consistent determination of the temperature distribution via the constraint of energy conservation. The energy balance includes the gains due to the…

Astrophysics · Physics 2007-11-02 Octavio Cardona , Lucio Crivellari , Eduardo Simonneau

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 discuss the problem of polarized radiative transfer in general relativity. We present a set of equations suitable for solving the problem numerically for the case of an arbitrary space-time metric, and show numerical solutions to example…

Instrumentation and Methods for Astrophysics · Physics 2017-06-28 Pauli Pihajoki , Antti Rantala , Peter H. Johansson

In this work, we present expressions for radiative heat transfer between pairs of spheres in a linear chain and between individual spheres and their environment. The expressions are valid for coated spheres of arbitrary size, spacing, and…

Mesoscale and Nanoscale Physics · Physics 2019-01-29 Braden Czapla , Arvind Narayanaswamy

In this work, we present an expression for the near-field thermal radiative transfer between two spheres with an arbitrary numbers of coatings. We numerically demonstrate that the spectrum of heat transfer between layered spheres exhibits…

Mesoscale and Nanoscale Physics · Physics 2017-09-13 Braden Czapla , Arvind Narayanaswamy

In a recent article the authors showed that the radiative Transfer equations with multiple frequencies and scattering can be formulated as a nonlinear integral system. In the present article, the formulation is extended to handle reflective…

Numerical Analysis · Mathematics 2023-06-12 Olivier Pironneau , Pierre-Henri Tournier

The difficulty of description of the radiative transfer in disordered photonic crystals arises from the necessity to consider on the equal footing the wave scattering by periodic modulations of the dielectric function and by its random…

Disordered Systems and Neural Networks · Physics 2009-10-16 M. V. Erementchouk , L. I. Deych , H. Noh , H. Cao , A. A. Lisyansky

The theory of heat transfer by electromagnetic radiation is based on the radiative transfer equation (RTE) for the radiation intensity, or equivalently on the Boltzmann transport equation (BTE) for the photon distribution. We focus in this…

Statistical Mechanics · Physics 2010-09-17 Thomas Christen , Frank Kassubek , Rudolf Gati