Related papers: Computation of atomic astrophysical opacities
Standard solar models (SSMs) constructed in accordance with old solar abundances are in reasonable agreement with seismically inferred results, but SSMs with new low-metal abundances disagree with the seismically inferred results. The…
The Sun is the most studied of all stars, and thus constitutes a benchmark for stellar models. However, our vision of the Sun is still incomplete, as illustrated by the current debate on its chemical composition. The problem reaches far…
Monochromatic opacities from the Opacity Project (OP) (Seaton et al.) have been augmented by hitherto missing inner-shell contributions (Badnell & Seaton). OP Rosseland-mean opacities are compared with results from OPAL (Iglesias & Rogers)…
Helioseismology provides a powerful tool to explore the deep interior of the Sun: for example, the adiabatic sound speed can be inferred with an accuracy of a few parts in 10,000. This has become a serious challenge to theoretical models of…
Previous computations of low temperature Rosseland and Planck mean opacities from Alexander & Ferguson (1994) are updated and expanded. The new computations include a more complete equation of state with more grain species and updated…
The calculation of line widths constitutes theoretical and computational challenges in the calculation of opacities of hot dense plasmas. Opacity models use line broadening approximations that are untested at stellar interior conditions.…
Is the Sun likely to have a more opaque interior than previously thought? The solar oxygen (or abundance) problem can be solved with higher interior opacities, reconciling abundance analyses based on 3D convective atmospheres with the…
The observed correlation between global low cloud amount and the flux of high energy cosmic rays supports the idea that ionization plays a crucial role in tropospheric cloud formation. We explore this idea quantitatively with a simple model…
The latest solar atmosphere models include non-LTE corrections and 3D hydrodynamic convection simulations. These models predict a significant reduction in the solar metal abundance, which leads to a serious conflict between helioseismic…
Estimates of the bulk metal abundance of the Sun derived from the latest generation of model atmospheres are significantly lower than the earlier standard values. In Paper I we demonstrated that a low solar metallicity is inconsistent with…
We construct updated solar models with different sets of solar abundances, including the most recent determinations by Asplund et al. (2009). The latter work predicts a larger ($\sim 10%$) solar metallicity compared to previous measurements…
The solar abundances have undergone a major downward revision in the last decade, reputedly as a result of employing 3D hydrodynamical simulations to model the inhomogeneous structure of the solar photosphere. The very low oxygen abundance…
Recent solar photospheric abundance analyses (Asplund et al. 2004, 2005; Lodders 2003) have revised downward the C, N, O, Ne, and Ar abundances by 0.15 to 0.2 dex compared to previous determinations of Grevesse & Sauval (1998). With these…
The standard solar model was so reliable that it could predict the existence of the massive neutrino. Helioseismology measurements were so precise that they could determine the depth of the convection zone. This agreement between theory and…
Recent revisions of the determination of the solar composition have resulted in solar models in marked disagreement with helioseismic inferences. The effect of the composition change on the model is largely caused by the change in the…
A new opacity model based on the Super-Transition-Array (STA) method for the calculation of monochromatic opacities of local thermodynamic equilibrium plasmas, was developed. The atomic code, named STAR (STA-Revised), is described and used…
Frequencies of intermediate-degree f-modes of the Sun seem to indicate that the solar radius is smaller than what is normally used in constructing solar models. We investigate the possible consequences of an error in radius on results for…
In the last decade, the photospheric abundances of the Sun had been revised several times by many observers. The standard solar models (SSM) constructed with the new low-metal abundances disagree with helioseismic results and detected…
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…
We examine the constraints imposed by helioseismic data on the solar heavy element abundances. In prior work we argued that the measured depth of the surface convection zone R_CZ and the surface helium abundance Y_surf were good metallicity…