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Related papers: The Classical Stellar Atmosphere Problem

200 papers

We briefly review some constraints (Owing to the limited number of pages of present review, only a sub-sample of the topics discussed during the talk are briefly summarized. For the interested readers we are pleased to send them upon…

Astrophysics · Physics 2009-11-13 S. Cassisi

We study the statistical mechanics of classical and quantum systems in non-equilibrium steady states. Emphasis is placed on systems in strong thermal gradients. Various measures and functional forms of observables are presented. The quantum…

Chaotic Dynamics · Physics 2007-05-23 Dimitri Kusnezov , Eric Lutz , Kenichiro Aoki

Radiative transfer calculations are essential for modeling planetary atmospheres. However, standard methods are computationally demanding and impose accuracy-speed trade-offs. High computational costs force numerical simplifications in…

Earth and Planetary Astrophysics · Physics 2025-11-03 Isaac Malsky , Tiffany Kataria , Natasha E. Batalha , Matthew Graham

In this paper we investigate statistical equilibrium of Ti in the atmospheres of late-type stars. The Ti I/Ti II level populations are computed with available experimental atomic data, except for photoionization and collision induced…

Solar and Stellar Astrophysics · Physics 2015-05-20 Maria Bergemann

Taking a novel approach, this paper discuss the structure of compact stars, an important topic in theoretical astrophysics. Adopting the Newtonian gravitation, we solve the hydrostatic equilibrium equation by imposing a simple…

Solar and Stellar Astrophysics · Physics 2014-07-22 Hilario Rodrigues

Using the method termed complex asteroseismology, we derive constraints on model atmospheres, in particular, on the NLTE effects. We fit simultaneously pulsational frequencies and the corresponding values of the nonadiabatic complex…

Solar and Stellar Astrophysics · Physics 2012-05-18 Wojciech Szewczuk , Przemysław Walczak , Jadwiga Daszyńska-Daszkiewicz

An inversion technique has been developed to recover LTE one-dimensional model photospheres for late-type stars from very high-resolution high signal-to-noise stellar line profiles. It is successfully applied to the Sun using a set of…

Astrophysics · Physics 2007-05-23 C. Allende Prieto , B. Ruiz Cobo , R. J. Garcia Lopez

Accelerated charges emit electromagnetic radiation and the consequent energy-momentum loss alters their trajectory. This phenomenon is known as radiation reaction and the Landau-Lifshitz (LL) equation is the classical equation of motion of…

High Energy Physics - Phenomenology · Physics 2021-07-14 A. Di Piazza , G. Audagnotto

Linear algebraic primitives are at the core of many modern algorithms in engineering, science, and machine learning. Hence, accelerating these primitives with novel computing hardware would have tremendous economic impact. Quantum computing…

Recently, the theory of symmetric teleparallel equivalent of general relativity (STEGR) has gained much interest in the cosmology and astrophysics community. Within this theory, we discuss the method of deriving a stellar isotropic model.…

General Relativity and Quantum Cosmology · Physics 2025-04-08 G. G. L. Nashed , Amare Abebe

A certain class of one-dimensional classical lattice models is considered. Using the method of abstract harmonic analysis explicit thermostatic properties of such models are derived. In particular, we discuss the low-temperature behavior of…

High Energy Physics - Theory · Physics 2007-05-23 Georg Junker

The formation of lithium lines in the atmosphere of C-rich giants is discussed. LTE and NLTE approximations are used to model lithium lines in the spectra of super Li-rich AGB stars. The system of equations of the statistical balance of…

Astrophysics · Physics 2011-05-23 Carlos Abia , Yakiv Pavlenko , Patrick de Laverny

The non-linearities of the dynamics of Earth artificial satellites are encapsulated by two formal integrals that are customarily computed by perturbation methods. Standard procedures begin with a Hamiltonian simplification that removes…

Dynamical Systems · Mathematics 2020-09-23 Martin Lara

An analytical linear solution of the fully compressible Euler equations is found, in the particular case of a stationary two dimensional flow that passes over an orographic feature with small height-width ratio. A method based on the…

Atmospheric and Oceanic Physics · Physics 2016-12-20 Juan Simarro , Petra Smolikova , Jozef Vivoda

Carbon abundances in late-type stars are important in a variety of astrophysical contexts. However C i lines, one of the main abundance diagnostics, are sensitive to departures from local thermodynamic equilibrium (LTE). We present a model…

Solar and Stellar Astrophysics · Physics 2019-04-24 A. M. Amarsi , P. S. Barklem , R. Collet , N. Grevesse , M. Asplund

Analyses of stellar spectra often begin with the determination of a number of parameters that define a model atmosphere. This work presents a prototype for an automated spectral classification system that uses a 15 nm-wide region around…

Astrophysics · Physics 2016-08-30 C. Allende Prieto

Density and temperature conditions in many stellar core (like the solar core) imply the presence of nonideal plasma effects with memory and long-range interactions between particles. This aspect suggests the possibility that the stellar…

Nuclear Theory · Physics 2017-08-23 A. Lavagno , P. Quarati

A new class of solutions describing analytical solutions for compact stellar structures has been developed within the tenets of General Relativity. Considering the inherent anisotropy in compact stars, a stable and causal model for…

General Relativity and Quantum Cosmology · Physics 2021-10-14 Jay Solanki , Bhashin Thakore

Analytic solutions to the nonlinear radiation diffusion equation with an instantaneous point source for a non-homogeneous medium with a power law spatial density profile, are presented. The solutions are a generalization of the well known…

Fluid Dynamics · Physics 2021-06-02 Menahem Krief

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