Related papers: Analysis of stellar spectra with 3D and NLTE model…
In the last decades, stellar atmosphere models have become a key tool in understanding massive stars. Applied for spectroscopic analysis, these models provide quantitative information on stellar wind properties as well as fundamental…
Stellar model atmospheres form the basis for any element abundance determination and hence are crucial ingredients for studies of stellar, galactic and cosmic evolution. With recent observational progress with the advent of 8m-class…
Most of the physical information about astrophysical objects is obtained via the analysis of their electromagnetic spectra. Observed data coupled with radiation transfer models in physical conditions representative of stars, planets,…
Recently 3D hydrodynamical simulations of stellar surface convection have become feasible thanks to advances in computer technology and efficient numerical algorithms. Available observational diagnostics indicate that these models are…
Present observational techniques provide stellar spectra with high resolution at a high signal-to-noise ratio over the complete wavelength range -- from the far infrared to the X-ray. NLTE effects are particularly important for hot stars,…
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,…
Stars play a decisive role in our Universe, from its beginning throughout its complete evolution. For a thorough understanding of their properties, evolution, and physics of their outer envelopes, stellar spectra need to be analyzed by…
We describe our method to construct line blanketed NLTE model atmospheres for hot stars. We employ the Accelerated Lambda Iteration and use statistical methods to deal with metal line blanketing.
This review presents basic equations for the solution of the NLTE radiative transfer problem for trace elements and methods for its solution are summarized. The importance of frequency coupling in radiative transfer in stellar atmospheres…
Methods of calculation of NLTE model atmosphere are discussed. The NLTE trace element procedure is compared with the full NLTE model atmosphere calculation. Differences between LTE and NLTE atmosphere modeling are evaluated. The ways of…
Various available codes for NLTE modeling and analysis of hot star spectra are reviewed. Generalizations of standard equations of kinetic equilibrium and their consequences are discussed.
One of the major tasks in interpretation of data from large-scale stellar surveys is to determine the fundamental atmospheric parameters such as effective temperature, surface gravity, and metallicity. In most on-going and upcoming…
New numerical models of line-driven stellar winds of late O stars are presented. Statistical equilibrium (NLTE) equations of the most abundant elements are solved. Properly obtained occupation numbers are used to calculate consistent…
Basic assumptions of the NLTE approximation in stellar atmospheres are summarized. The assumptions of thermodynamic equilibrium, local thermodynamic equilibrium (LTE), and non-LTE (NLTE) are compared. It is emphasized that LTE is a poor…
I describe recent progress in terms of 3D hydrodynamical model atmospheres and 3D line formation and their applications to stellar abundance analyses of late-type stars. Such 3D studies remove the free parameters inherent in classical 1D…
In this review given at the Hot and Cool: Bridging Gaps in Massive Star Evolution conference, I present the state of the art in red supergiant star atmosphere modelling. The last generation of hydrostatic 1D LTE MARCS models publicly…
Physically realistic models of stellar spectra are needed in a variety of astronomical studies, from the analysis of fundamental stellar parameters, to studies of exoplanets and stellar populations in galaxies. Here we present a new version…
With the goal of producing a reliable set of model atoms and singly-ionized ions for use in building NLTE model atmospheres, we have combined measured energy levels, critically-compiled line transition probabilities, and resonance-averaged…
The current status of NLTE model atmosphere calculations of A type stars is reviewed. During the last decade the research has concentrated on solving the restricted NLTE line formation problem for trace elements assuming LTE model…
Theoretical atmosphere models provide the basis for a variety of applications in astronomy. In simplified one-dimensional (1D) atmosphere models, convection is usually treated with the mixing length theory despite its well-known…