Related papers: Quantitative comparison of opacities calculated us…
We evaluate the logarithmic derivative of the depth of the solar convective zone with respect to the logarithm of the radiative opacity. We use this expression to show that the radiative opacity near the base of the solar convective zone…
Here, we compare radiative accelerations (g_rad) derived from the new Opacity Project (OP) data with those computed from OPAL and some previous data from OP. For the case where we have full data from OPAL, the differences in the Rosseland…
We describe a new method for the computation of opacity distribution functions (ODFs) useful to calculate one-dimensional model atmospheres in local thermal equilibrium (LTE). The new method is fast enough to be applied on current…
The computation of radiative opacity or emissivity of hot dense matter is a challenging task. It requires accounting for an immense number of energy levels and lines across various excitation and ionization states. Whether in local…
The chemical element nickel is of particular interest in stellar physics. In the layers in which the Fe-peak elements dominate the mean opacity (the so-called Z-bump), Ni is the second contributor to the Rosseland opacity after iron,…
We present a set of gas-phase Planck mean and Rosseland mean opacity tables applicable for simulations of star and planet formation, stellar evolution, disk modelling at various metallicities in hydrogen-rich environments. The tables are…
A general formulation is employed to study and quantitatively ascertain the effect of plasma broadening of {\it intrinsic} autoionizing (AI) resonances in photoionization cross sections. In particular, R-matrix data for iron ions described…
Context. Realistic 3D time-dependent simulations of stellar near-surface convection employ the opacity binning method for efficient and accurate computation of the radiative energy exchange. The method provides several orders of magnitude…
Photoionization and recombination cross sections and rate coefficients are calculated for Li-like Fe XXIV and He-like Fe XXV using the Breit-Pauli R-matrix (BPRM) method. A complete set of total and level-specific parameters is obtained to…
The optimization of an optical system benefits greatly from a study of its aberrations and an identification of each of its elements' contribution to the overall aberration figures. The matrix formalism developed by one of the authors was…
We report extensive calculations of the decay properties of fine-structure K-vacancy levels in Fe X-Fe XVII. A large set of level energies, wavelengths, radiative and Auger rates, and fluorescence yields has been computed using three…
A new collection of photodissociation and photoionisation cross sections for 102 atoms and molecules of astrochemical interest has been assembled, along with a brief review of the basic processes involved. These have been used to calculate…
Electron conduction opacities are one of the main physics inputs for the calculation of low- and intermediate-mass stellar models, and a critical question is how to bridge calculations for moderate and strong degeneracy, which are…
Seismology of stars is strongly developing. To address this question we have formed an international collaboration OPAC to perform specific experimental measurements, compare opacity calculations and improve the opacity calculations in the…
It is shown that above the temperature of maximum abundance, recombination rates into the excited states of He-like ions that are calculated using earlier, more approximate methods differ markedly from rates obtained from recent…
We apply the $R$-matrix method in Distorted Wave Born Approximation (DWBA) calculations. The internal wave functions are expanded over a Lagrange mesh, which provides an efficient and fast technique to compute matrix elements. We first…
We build differential-reddening maps for 66 Galactic globular clusters (GCs) with archival HST WFC/ACS F606W and F814W photometry. Because of the different GC sizes (characterised by the half-light radius $R_h$) and distances to the Sun,…
We demonstrate a strategy for simulating wide-range X-ray scattering patterns, which spans the small- and wide scattering angles as well as the scattering angles typically used for Pair Distribution Function (PDF) analysis. Such simulated…
We present new calculations of atomic data needed to model autoionizing states of Fe XVI. We compare the state energies, radiative and excitation data with a sample of results from previous literature. We find a large scatter of results,…
Nowadays, several opacity codes are able to provide data for stellar structure models, but the computed opacities may show significant differences. In this work, we present state-of-the-art precise spectral opacity calculations, illustrated…