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تسجيل مستخدم جديدRecalculation of Astrophysical Opacities: Overview, Methodology and Atomic Calculations
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A review of a renewed effort to recalculate astrophysical opacities using the R-Matrix method is presented. The computational methods and new extensions are described. Resulting enhancements found in test calculations under stellar interior conditions compared to the Opacity Project could potentially lead to the resolution of the solar abundances problem, as well as discrepancies between recent experimental measurements at the Sandia Z-pinch inertial confinement fusion device and theoretical opacity models. Outstanding issues also discussed are: (i) accuracy, convergence, and completeness of atomic calculations, (ii) improvements in the Equation-of-State of high-temperature-density plasmas, and (iii) redistribution of resonant oscillator strength in the bound-free continuum, and (iv) plasma broadening of auotionizing resonances.
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Fundamental atomic parameters, such as oscillator strengths, play a key role in modelling and understanding the chemical composition of stars in the universe. Despite the significant work underway to produce these parameters for many astrophysically
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Availability of reliable atomic and molecular opacity tables is essential in a wide variety of astronomical modeling: the solar and stellar interiors, stellar and planetary atmospheres, stellar evolution, pulsating stars, and protoplanetary disks, to
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This work reports new experimental radiative lifetimes and calculated oscillator strengths for transitions from 3d8 4d levels of astrophysical interest in singly ionized nickel. Radiative lifetimes of seven high-lying levels of even parity in Ni II (
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The present debate on the reliability of astrophysical opacities has reached a new climax with the recent measurements of Fe opacities on the Z-machine at the Sandia National Laboratory citep{Bailey2015}. To understand the differences between theoret
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