Related papers: Solar opacity calculations using the super-transit…
In the past years we have made great efforts to reduce the statistical and systematic uncertainties in stellar parameter and chemical abundance determinations of early B-type stars. Both the construction of robust model atoms for non-LTE…
Context. The solar irradiance is known to change on time scales of minutes to decades, and it is suspected that its substantial fluctua- tions are partially responsible for climate variations. Aims. We are developing a solar atmosphere code…
An ultrastable optical clock based on neutral atoms trapped in an optical lattice is proposed. Complete control over the light shift is achieved by employing the $5s^2 {}^1S_0 \to 5s5p {}^3P_0$ transition of ${}^{87}{\rm Sr}$ atoms as a…
Laboratory (laser and Z-pinch) opacity measurements of well-characterized plasmas provide data to assist inertial confinement fusion, astrophysics and atomic-physics research. In order to test the atomic-physics codes devoted to the…
The research focuses on determining the metallicity ([Fe/H]) predicted in the solar twin stars by using various regression modeling techniques which are, Random Forest, Linear Regression, Decision Tree, Support Vector, and Gradient…
The trace anomaly $\Delta\equiv 1/3-P/\varepsilon=1/3-\phi$ quantifies the possibly broken conformal symmetry in supradense matter under pressure $P$ at energy density $\varepsilon$. Perturbative QCD (pQCD) predicts a vanishing $\Delta$ at…
Combination frequencies are not solutions of the perturbed stellar structure equations. In dense power spectra from a light curve of a given multi-periodic pulsating star, they can compromise the mode identification in an asteroseismic…
The light emitted from the stellar photosphere serves as a unique signature for the nature of stars. The behaviour of these stellar lines depend upon the surface temperature, mass, evolutionary status and chemical composition of the star.…
We report on two distinct computational approaches to self-consistently measure photospheric properties of large samples of stars. Both procedures consist of a set of several semi-integrated tasks based on shell and Python scripts, which…
We review the theory of electron-conduction opacity, a fundamental ingredient in the computation of low-mass stellar models; shortcomings and limitations of the existing calculations used in stellar evolution are discussed. We then present…
In this review presented at the Symposium A stellar journey in Uppsala, June 2008, I give my account of the historical development of the MARCS code from the first version published in 1975 and its premises to the 2008 grid. It is shown…
The reported new type of all-solid-state, inorganic solar cell will be discussed by a semiclassical light-matter interaction method. The molecular compound will be treated by a three times two-level coupled quantum system. The equation of…
We present a technique to treat systems with very many levels, like molecules, in non-LTE. This method is based on a superlevel formalism coupled with rate operator splitting. Superlevels consist of many individual levels that are assumed…
Context. Previous studies have suggested that the Sun is relatively depleted in refractory elements compared to other solar twins or analogs, potentially as a result of planet formation. However, such conclusions are often limited by…
Opacity enhancements for stellar interior conditions have been explored to explain observed pulsation frequencies and to extend the pulsation instability region for B-type main-sequence variable stars. For these stars, the pulsations are…
We present an updated version of our standard solar model (SSM) where helium and heavy elements diffusion is included and the improved OPAL equation of state (Rogers 1994, Rogers Swenson \& Iglesias 1996) is used. In such a way the EOS is…
Due to their wide wavelength coverage across the millimetre to centimetre (mm - cm) range and their increased sensitivity, modern interferometric arrays facilitate observations of the thermal and non-thermal emission from different stellar…
Lanthanides play most important roles in the opacities for kilonova, ultraviolet-optical-infrared emission from neutron star mergers. Although several efforts have been made to construct atomic data, the accuracy in the opacity is not fully…
An electronically variational approach to the calculation of atomic hyperfine structure transition energies under the influence of static external electric fields is presented. The method avoids the calculation of intermediate atomic states…
Measurements of visible and near-infrared reflection (0.38-5 {\mu}m) and mid to far infrared emission (5-200 {\mu}m) from telescope and satellite remote sensing instruments make it possible to investigate the composition of planetary…