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We report on non-LTE Ne abundances for a sample of B-type stellar members of the Orion Association. The abundances were derived by means of non-LTE fully metal-blanketed model atmospheres and extensive model atoms with updated atomic data.…

Astrophysics · Physics 2009-11-11 Katia Cunha , Ivan Hubeny , Thierry Lanz

Context. The Galactic chemical evolution of sulphur is still under debate. At low metallicities some studies find no correlation between [S/Fe] and [Fe/H], others find [S/Fe] increasing towards lower metallicities, and still others find a…

Astrophysics of Galaxies · Physics 2013-12-18 E. Matrozis , N. Ryde , A. K. Dupree

Europium plays a key role in studies of nucleosynthesis in the rapid (r-) process of neutron capture nuclear reactions and the evolution of the r-process element abundances in galaxies. We refine the method for analyzing the Eu~II lines in…

Solar and Stellar Astrophysics · Physics 2026-04-27 L. I. Mashonkina , S. A. Yakovleva

We present three-dimensional (3D) non-local thermodynamic equilibrium (non-LTE) radiative transfer calculations for silicon in the solar photosphere, using an extensive model atom that includes recent, realistic neutral hydrogen collisional…

Solar and Stellar Astrophysics · Physics 2016-09-28 A. M. Amarsi , M. Asplund

We present oxygen abundances derived from both the permitted and forbidden oxygen lines for 55 subgiants and giants with [Fe/H] values between -2.7 and solar with the goal of understanding the discrepancy in the derived abundances. A first…

Astrophysics · Physics 2009-11-10 Jon P. Fulbright , Jennifer A. Johnson

{The \ion{Na}{x} X-ray lines between 10.9 and 11.2~\AA\ have attracted little attention but are of interest since they enable an estimate of the coronal abundance of Na to be made. This is of great interest in the continuing debate on the…

Solar and Stellar Astrophysics · Physics 2015-05-19 K. J. H. Phillips , K. M. Aggarwal , E. Landi , F. P. Keenan

The non-local thermodynaic equilibrium (non-LTE) line formation for the two ions of zirconium is considered through a range of spectral types when the Zr abundance varies from the solar value down to [Zr/H] = -3. The model atom was built…

Solar and Stellar Astrophysics · Physics 2015-05-27 A. Velichko , L. Mashonkina , H. Nilsson

We present non-Local Thermodynamic Equilibrium (non-LTE) calculations for neutral carbon spectral line formation, carried out for a grid of model atmospheres covering the range of late-type stars. The results of our detailed calculations…

Astrophysics · Physics 2015-06-24 Damian Fabbian , Martin Asplund , Mats Carlsson , Dan Kiselman

We present a near-infrared abundance analysis of 46 solar analogs with known ages, observed with the WINERED WIDE-mode spectrograph at a resolution of $\lambda/\Delta\lambda = 28,000$. Using an empirically calibrated, line-by-line approach…

We perform non-LTE calculations of lithium in late-type stars for a wide range of stellar parameters, including quantum mechanical cross-sections for collisions with neutral hydrogen and the negative hydrogen ion. Non-LTE abundance…

Solar and Stellar Astrophysics · Physics 2015-05-13 K. Lind , M. Asplund , P. S. Barklem

We performed non-LTE calculations for O I with the plane-parallel model atmospheres for a set of stellar parameters corresponding to A-K type stars. The model atom of Przybilla et al. (2000) was updated using the best theoretical and…

Solar and Stellar Astrophysics · Physics 2013-02-06 T. M. Sitnova , L. I. Mashonkina , T. A. Ryabchikova

Phosphorus-bearing species are an essential key to form life on Earth, however they have barely been detected in the interstellar medium. Since only PN and PO have been identified so far towards star-forming regions, the chemical formation…

Palladium is one of poorly observed neutron-capture elements. Abundance determinations for stellar samples covering a broad metallicity range are needed for better understanding the mechanisms of Pd synthesis during the Galaxy evolution. We…

Solar and Stellar Astrophysics · Physics 2025-11-26 L. Mashonkina , A. Smogorzhevskii

The abundance of potassium is derived from X-ray lines observed during flares by the RESIK instrument on the solar mission CORONAS-F between 3.53 A and 3.57 A. The lines include those emitted by He-like K and Li-like K dielectronic…

Solar and Stellar Astrophysics · Physics 2015-05-14 J. Sylwester , B. Sylwester , K. J. H. Phillips , V. D. Kuznetsov

We present non-LTE oxygen abundances for a sample of B stars in the Orion association. The abundance calculations included non-LTE line formation and used fully blanketed non-LTE model atmospheres. The stellar parameters were the same as…

Solar and Stellar Astrophysics · Physics 2015-05-30 K. Cunha , I. Hubeny , T. Lanz

Aims: To determine the neon-to-oxygen abundance in the quiet Sun, a proxy for the photospheric abundance ratio. Method: An emission measure method applied to extreme ultraviolet emission lines of Ne IV-VI and O III-V ions observed by the…

Astrophysics · Physics 2009-11-11 P. R. Young

Boron abundances in A- and B-type stars may be a successful way to track evolutionary effects in these hot stars. The light elements -- Li, Be, and B -- are tracers of exposure to temperatures more moderate than those in which the H-burning…

Astrophysics · Physics 2007-05-23 Kim A. Venn , David L. Lambert , Michael Lemke

Accurately known stellar lithium abundances may be used to shed light on a variety of astrophysical phenomena such as Big Bang nucleosynthesis, radial migration, ages of stars and stellar clusters, and planet engulfment events. We present a…

Solar and Stellar Astrophysics · Physics 2020-10-30 E. Wang , T. Nordlander , M. Asplund , A. M. Amarsi , K. Lind , Y. Zhou

The infrared (IR) range is extremely useful in the context of chemical abundance studies of the gas-phase interstellar medium (ISM) due to the large variety of ionic species traced in this regime, the negligible effects from dust…

Our recent re-analysis of the solar photospheric spectra with non-local thermodynamic equilibrium (non-LTE) models resulted in higher metal abundances compared to previous works. When applying the new chemical abundances to Standard Solar…

Solar and Stellar Astrophysics · Physics 2022-09-07 Manuel A. Bautista , Maria Bergemann , Helena Carvajal Gallego , Sébastien Gamrath , Patrick Palmeri , Pascal Quinet
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