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Related papers: NLTE study of scandium in the Sun

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We present a model atom for C I - C II - C III - C IV using the most up-to-date atomic data and evaluated the non-local thermodynamic equilibrium (NLTE) line formation in classical 1D atmospheric models of O-B-type stars. Our models predict…

Solar and Stellar Astrophysics · Physics 2019-11-06 Sofya Alexeeva , Kozo Sadakane , Masayoshi Nishimura , Junju Du , Shaoming Hu

For the well studied halo star HD 122563 and the four stars in the globular cluster NGC 6397, we determine NLTE abundances of iron using classical plane-parallel model atmospheres. Each star reveals a discrepancy in abundances between the…

Solar and Stellar Astrophysics · Physics 2013-03-05 L. Mashonkina , H. -G. Ludwig , A. Korn , T. Sitnova , E. Caffau

CONTEXT: In recent years, the solar chemical abundances have been studied in considerable detail because of discrepant values of solar metallicity inferred from different indicators, i.e., on the one hand, the "sub-solar" photospheric…

Solar and Stellar Astrophysics · Physics 2015-05-13 E. Caffau , E. Maiorca , P. Bonifacio , R. Faraggiana , M. Steffen , H. -G. Ludwig , I. Kamp , M. Busso

Based on detailed 2D radiation hydrodynamics (RHD) simulations, we have investigated the effects of photospheric temperature inhomogeneities induced by convection on spectroscopic determinations of the lithium abundance. Computations have…

Astrophysics · Physics 2007-05-23 R. Cayrel , M. Steffen

We perform the non-local thermodynamic equilibrium (NLTE) calculations for Ca I-II with the updated model atom that includes new quantum-mechanical rate coefficients for Ca I + H I collisions from two recent studies, that is, by Barklem and…

Solar and Stellar Astrophysics · Physics 2017-09-13 L. Mashonkina , T. Sitnova , A. K. Belyaev

In an effort to estimate the largely unknown effects of photospheric temperature fluctuations on spectroscopic abundance determinations, we have studied the problem of LTE line formation in the inhomogeneous solar photosphere based on…

Astrophysics · Physics 2009-11-07 M. Steffen , H. Holweger

Non-local thermodynamical equilibrium (non-LTE) line formation for neutral and singly-ionized iron is considered through a range of spectral types when the effective temperature varies from 6500 K up to 8500 K, the gravity from log g = 4…

Solar and Stellar Astrophysics · Physics 2011-04-25 L. Mashonkina

We re-evaluate the abundances of the elements in the Sun from copper ($Z=29$) to thorium ($Z=90$). Our results are mostly based on neutral and singly-ionised lines in the solar spectrum. We use the latest 3D hydrodynamic solar model…

Solar and Stellar Astrophysics · Physics 2014-12-17 Nicolas Grevesse , Pat Scott , Martin Asplund , A. Jacques Sauval

The present-day abundance of beryllium in the solar atmosphere provides clues about mixing mechanisms within stellar interiors. However, abundance determinations based on the Be II 313.107 nm line are prone to systematic errors due to…

Solar and Stellar Astrophysics · Physics 2024-09-09 A. M. Amarsi , D. Ogneva , G. Buldgen , N. Grevesse , Y. Zhou , P. S. Barklem

Determinations of the solar oxygen content relying on the neutral forbidden transition at 630 nm depend upon the nickel abundance, due to a Ni I blend. Here we rederive the solar nickel abundance, using the same ab initio 3D hydrodynamic…

Astrophysics · Physics 2009-01-27 Pat Scott , Martin Asplund , Nicolas Grevesse , A. Jacques Sauval

We investigate the non-local thermodynamic equilibrium (NLTE) analysis for \ion{Cu}{1} lines with the updated model atom that includes quantum-mechanical rate coefficients of Cu\,$+$\,H and Cu$^+$\,$+$\,H$^-$ inelastic collisions from the…

Solar and Stellar Astrophysics · Physics 2022-08-31 Xiaodong Xu , Jianrong Shi , Xiaofeng Wang

Silver is an important light neutron-capture element whose stellar abundances help constrain the origin of the weak r-process. The Sun is an important reference point for such studies; moreover, being a moderately volatile element in CI…

Solar and Stellar Astrophysics · Physics 2026-05-08 Sema Caliskan , Anish M. Amarsi , Per Jönsson , Nicolas Grevesse , Bijaya K. Sahoo

Zirconium (Zr), together with strontium and yttrium, is an important element in the understanding of the Galactic nucleosynthesis. In fact, the triad Sr-Y-Zr constitutes the first peak of s-process elements. Despite its general relevance…

Solar and Stellar Astrophysics · Physics 2015-05-20 Elisabetta Caffau , Rosanna Faraggiana , Hans-Günter Ludwig , Piercarlo Bonifacio , Matthias Steffen

Un-evolved, very metal-poor stars are the most important tracers of the cosmic abundance of lithium in the early universe. Combining the standard Big Bang nucleosynthesis model with Galactic production through cosmic ray spallation, these…

Solar and Stellar Astrophysics · Physics 2015-06-16 Karin Lind , Jorge Melendez , Martin Asplund , Remo Collet , Zazralt Magic

The recent downward revision of the solar photospheric abundances now leads to severe inconsistencies between the theoretical predictions for the internal structure of the Sun and the results of helioseismology. There have been claims that…

Astrophysics · Physics 2009-11-13 T. Morel , K. Butler

We present a detailed study of the non-Local Thermodynamic Equilibrium (non-LTE) formation of the high-excitation neutral oxygen 777 nm triplet in MARCS model atmospheres representative of late-type stars with spectral types F to K. We…

Solar and Stellar Astrophysics · Physics 2015-05-13 D. Fabbian , M. Asplund , P. S. Barklem , M. Carlsson , D. Kiselman

We study the effects of non-local thermodynamic equilibrium (NLTE) on the abundance analysis of barium, magnesium, and manganese from integrated light spectroscopy, as typically applied to the analysis of extra-galactic star clusters and…

Solar and Stellar Astrophysics · Physics 2019-07-03 Philipp Eitner , Maria Bergemann , Soeren Larsen

We present magnesium abundances derived from high resolution spectra using several Mg I and two high excitation Mg II lines for 19 metal-poor stars with [Fe/H] values between -1.1 and +0.2. The main goal is to search for systematic…

Astrophysics · Physics 2016-08-30 Carlos Abia , Lyudmila Mashonkina

Context. The pursuit of more realistic spectroscopic modelling and consistent abundances has led us to begin a new series of papers designed to improve current solar and stellar abundances of various atomic species. To achieve this, we have…

Solar and Stellar Astrophysics · Physics 2020-02-12 A. J. Gallagher , M. Bergemann , R. Collet , B. Plez , J. Leenaarts , M. Carlsson , S. A. Yakovleva , A. K Belyaev

Classical Cepheids (CCs) have long been considered excellent tracers of the chemical evolution of the Milky Way's young disk. We present a homogeneous, NLTE spectroscopic analysis of 401 Galactic CCs, based on 1,351 high-resolution optical…

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