Related papers: Detailed Opacity Calculations for Stellar Models
Time-dependent cooling processes are of paramount importance in the evolution of astrophysical gaseous nebulae and, in particular, when radiative shocks are present. The present work introduces a necessary set of tools that can be used to…
Model atoms are an integral part in the solution of non-LTE problems. They comprise the atomic input data that are used to specify the statistical equilibrium equations and the opacities and emissivities of radiative transfer. A realistic…
We report on modelling in stellar astrophysics with the ANTARES code. First, we describe properties of turbulence in solar granulation as seen in high-resolution calculations. Then, we turn to the first 2D model of pulsation-convection…
Solving the continuum radiative transfer equation in high opacity media requires sophisticated numerical tools. In order to test the reliability of such tools, we present a benchmark of radiative transfer codes in a 2D disc configuration.…
High-resolution images of the solar surface show a granulation pattern of hot rising and cooler downward-sinking material -- the top of the deep-reaching solar convection zone. Convection plays a role for the thermal structure of the solar…
We provide a theoretical analysis of Radiative Shocks, defined as supercritical shocks accompanied by an ionization wave in front of the density jump. In particular, we look at the influence of opacity variation with temperature and photon…
Radiation contributes to the acceleration of large-scale flows in various astrophysical environments because of the strong opacity in spectral lines. Quantification of the associated force is crucial to understanding these line-driven…
The relative populations in rotational transitions of CO can be useful for inferring gas conditions and excitation mechanisms at work in the interstellar medium. We present CO emission lines from rotational transitions observed with…
The surface structure of the magnetic field in stars is one part of the information about the surface inhomogeneities like brightness, movement or chemical composition, which is contained in the integral radiation flux but distorted beyond…
One of the largest sources of uncertainty in stellar models is caused by the treatment of convection in stellar envelopes. One dimensional stellar models often make use of the mixing length or equivalent approximations to describe…
(Summary) Making use of scaling relations between the central and the total galaxy luminosity of a dark matter halo as a function of the halo mass, and the scatter in these relations, we present an empirical model to describe the luminosity…
We develop the formalism for determining the quasinormal modes of general relativistic multi-fluid compact stars in such a way that the impact of superfluid gap data can be assessed. Our results represent the first attempt to study true…
Sensitive measurements of the linearly polarized spectra of stars can be used to deduce geometric properties of their otherwise unresolved circumstellar environments. This paper describes some of the evidence for optical pumping and…
Opacities and chemical abundance data are crucial ingredients of ultracool dwarf and extrasolar giant planet atmosphere models. We report here on the detailed sources of molecular opacity data employed by our group for this application. We…
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…
Modern stellar structure and evolution theory experiences a lack of observational calibrations for the interior physics of intermediate- and high-mass stars. This leads to discrepancies between theoretical predictions and observed phenomena…
{We aim to demonstrate the effect of atmospheric inhomogeneities on the emergent specific intensity and radiation flux of a spectral line radiation.} {We self-consistently solve the NLTE problem for a two-level atom in a 3D atmosphere using…
In the previous papers we derived cosmological equations for models with Gurzadyan-Xue dark energy, have performed their qualitative analysis and, particularly, have revealed a remarkable hidden invariance in the models with respect to the…
Precise fundamental atmospheric stellar parameters and abundance determination of individual elements in stars are important for all stellar population studies. Non-Local Thermodynamic Equilibrium (Non-LTE; hereafter NLTE) models are often…
Context. Recently our ability to study stars using asteroseismic techniques has increased dramatically, largely through the use of space based photometric observations. Work has also been done using ground based spectroscopic observations…