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相关论文: Formation of MnI lines in the solar atmosphere

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Manganese (Mn) is a key Fe-group elements, commonly employed in stellar population and nucleosynthesis studies to explore the role of SN Ia. We have developed a new non-local thermodynamic equilibrium (NLTE) model of Mn, including new…

NLTE line formation calculations of FeI in the solar atmosphere are extended to include weak optical lines. Previously established atomic models are used to discriminate between different ways of treating collisional interaction processes.…

天体物理学 · 物理学 2009-11-07 T. Gehren , A. J. Korn , J. Shi

Non-local thermodynamical equilibrium (NLTE) line formation for Mg I and Mg II lines is considered in classical 1D-LTE model atmospheres of the Sun and 17 stars with reliable atmospheric parameters and in a broad range of spectral types:…

太阳与恒星天体物理 · 物理学 2018-10-31 Sofya Alexeeva , Tatiana Ryabchikova , Lyudmila Mashonkina , Shaoming Hu

We investigate the formation of neutral and singly ionized scandium lines in the solar photospheres. The research is aimed derive solar $\log gf\epsilon_{\odot}$(Sc) values for scandium lines, which will later be used in differential…

天体物理学 · 物理学 2008-02-20 H. W. Zhang , T. Gehren , G. Zhao

Following our solar work, we perform NLTE calculations of the Mn abundance for fourteen stars with [Fe/H] from 0 to -2.5, mainly to show how NLTE affects Mn abundances in cool stars of different metallicities.The spectrum synthesis and Mn…

天体物理学 · 物理学 2009-11-13 Maria Bergemann , Thomas Gehren

A new model atom of nitrogen was developed using the energy levels of N I from laboratory measurements and also predicted in atomic structure calculations and the most up-to-date atomic data for computing radiative and collisional rates of…

太阳与恒星天体物理 · 物理学 2024-06-18 L. I. Mashonkina , T. A. Ryabchikova

We present LTE and NLTE atmospheric models of a star with solar parameters, and study the effect of treating many thousands of Iron group lines out of LTE on the computed atmospheric structure, overall absolute flux distribution, and the…

天体物理学 · 物理学 2009-11-10 C. I. Short , P. H. Hauschildt

Motivated by the controversy over the surface metallicity of the Sun, we present a re-analysis of the solar photospheric oxygen (O) abundance. New atomic models of O and Ni are used to perform Non-Local Thermodynamic Equilibrium (NLTE)…

The possibility of significant systematic errors due to the use of 1D homogeneous atmospheres in lithium-abundance determinations of cool stars motivates a study of non-local-thermodynamic-equilibrium (NLTE) effects on Li I line formation…

天体物理学 · 物理学 2009-10-30 Dan Kiselman

Magnesium abundances of cool stars with different metallicities are important for understanding the galactic chemical evolution. This study tests atomic data used in stellar magnesium abundance analyses. We evaluate non-local…

太阳与恒星天体物理 · 物理学 2015-06-12 Lyudmila Mashonkina

Nitrogen is an important element in various fields of stellar and Galactic astronomy, and the solar nitrogen abundance is crucial as a yardstick for comparing different objects in the cosmos. In order to obtain a precise and accurate value…

太阳与恒星天体物理 · 物理学 2020-04-29 A. M. Amarsi , N. Grevesse , J. Grumer , M. Asplund , P. S. Barklem , R. Collet

Different simplified approaches are used to account for the non-local thermodynamic equilibrium (NLTE) effects with 3D hydrodynamical model atmospheres. In certain cases, chemical abundances are derived in 1D NLTE and corrected for the 3D…

太阳与恒星天体物理 · 物理学 2016-02-17 J. Klevas , A. Kučinskas , M. Steffen , E. Caffau , H. -G. Ludwig

In this paper we investigate statistical equilibrium of Ti in the atmospheres of late-type stars. The Ti I/Ti II level populations are computed with available experimental atomic data, except for photoionization and collision induced…

太阳与恒星天体物理 · 物理学 2015-05-20 Maria Bergemann

The current analysis is dedicated to a detailed investigation of the non-Local Thermodynamic Equilibrium (NLTE) effects influencing the formation of the Fe I 6173 A line, which is widely used by many instruments including the Helioseismic…

太阳与恒星天体物理 · 物理学 2023-01-25 H. N. Smitha , M. van Noort , S. K. Solanki , J. S. Castellanos Durán

The precise analysis of properties of planetary nebulae is strongly dependent on good models for the stellar ionizing spectrum. Observations in the UV - X-ray wavelength range as well as NLTE model atmosphere calculations of spectra of…

天体物理学 · 物理学 2009-11-07 Thomas Rauch

We determine Mg abundances in 6 Gaia benchmark stars using theoretical one-dimensional (1D) hydrostatic model atmospheres, as well as temporally- and spatially-averaged 3D model atmospheres (<3D>). The stars cover a range of Teff from 4700…

太阳与恒星天体物理 · 物理学 2017-09-27 Maria Bergemann , Remo Collet , Anish M. Amarsi , Mikhail Kovalev , Gregory Ruchti , Zazralt Magic

We have used our PHOENIX multi-purpose model atmosphere code to calculate atmospheric models that represent novae in the optically thick wind phases of their outburst. We have improved the treatment of NLTE effects by expanding the number…

天体物理学 · 物理学 2009-10-31 C. Ian Short , Peter H. Hauschildt , E. Baron

The statistical equilibrium of neutral and ionised silicon in the solar photosphere is investigated. Line formation is discussed and the solar silicon abundance determined. High-resolution solar spectra were used to determine solar $\log…

天体物理学 · 物理学 2009-11-13 J. R. Shi , T. Gehren , K. Butler , L. I. Mashonkina , G. Zhao

We construct a comprehensive model atom for TiI-II using more than 3600 measured and predicted energy levels of TiI and 1800 energy levels of TiII, and quantum mechanical photoionisation cross-sections. Non-local thermodynamical equilibrium…

太阳与恒星天体物理 · 物理学 2016-07-27 T. M. Sitnova , L. I. Mashonkina , T. A. Ryabchikova

Aluminium plays a key role in studies of the chemical enrichment of the Galaxy and of globular clusters. However, strong deviations from LTE (non-LTE) are known to significantly affect the inferred abundances in giant and metal-poor stars.…

太阳与恒星天体物理 · 物理学 2017-11-28 Thomas Nordlander , Karin Lind
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