Search Results - "Sitnova, T."

A non-local thermodynamical equilibrium line formation for neutral and singly ionized titanium in model atmospheres of reference A–K stars by Sitnova, T. M., Mashonkina, L. I., Ryabchikova, T. A.

“…We construct a model atom for Ti i–ii using more than 3600 measured and predicted energy levels of Ti i and 1800 energy levels of Ti ii, and quantum mechanical…”
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SYSTEMATIC NON-LTE STUDY OF THE −2.6 ≤ [Fe/H] ≤ 0.2 F AND G DWARFS IN THE SOLAR NEIGHBORHOOD. II. ABUNDANCE PATTERNS FROM Li TO Eu by Zhao, G., Mashonkina, L., Yan, H. L., Alexeeva, S., Kobayashi, C., Pakhomov, Yu, Shi, J. R., Sitnova, T., Tan, K. F., Zhang, H. W., Zhang, J. B., Zhou, Z. M., Bolte, M., Chen, Y. Q., Li, X., Liu, F., Zhai, M.

“…ABSTRACT For the first time, we present an extensive study of stars with individual non-LTE (NLTE) abundances for 17 chemical elements from Li to Eu in a…”
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Detailed abundances of the wide pairs of stars with and without planets: the binary systems 16 Cyg and HD 219542 by Ryabchikova, T, Pakhomov, Yu, Mashonkina, L, Sitnova, T

“…ABSTRACT We present results of the comparative analysis of the two wide binary systems – 16 Cyg, with a giant gas planet orbiting around 16 Cyg B, and…”
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Non-LTE abundances of zinc in different spectral type stars and the Galactic [Zn/Fe] trend based on quantum-mechanical data on inelastic processes in zinc-hydrogen collisions by Sitnova, T M, Yakovleva, S A, Belyaev, A K, Mashonkina, L I

“…ABSTRACT We present a new model atom of Zn i-Zn ii based on the most up-to-date photoionization cross-sections, electron-impact excitation rates, and rate…”
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Chemical diversity among A–B stars with low rotational velocities: non-LTE abundance analysis by Mashonkina, L, Ryabchikova, T, Alexeeva, S, Sitnova, T, Zatsarinny, O

“…ABSTRACT We present accurate element abundance patterns based on the non-local thermodynamic equilibrium (non-LTE, NLTE) line formation for 14 chemical…”
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Accuracy of atmospheric parameters of FGK dwarfs determined by spectrum fitting by Ryabchikova, T., Piskunov, N., Pakhomov, Yu, Tsymbal, V., Titarenko, A., Sitnova, T., Alexeeva, S., Fossati, L., Mashonkina, L.

“…We performed extensive tests of the accuracy of atmospheric parameter determination for FGK stars based on the spectrum fitting procedure Spectroscopy Made…”
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A NLTE line formation for neutral and singly ionized calcium in model atmospheres of B-F stars by Sitnova, T M, Mashonkina, L I, Ryabchikova, T A

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1D non-LTE corrections for chemical abundance analyses of very metal-poor stars by Mashonkina, L, Pakhomov, Yu, Sitnova, T, Smogorzhevskii, A, Jablonka, P, Hill, V

“…ABSTRACT Detailed chemical abundances of very metal-poor (VMP; [Fe/H] < −2) stars are important for better understanding the first stars, early star formation,…”
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Ultra metal-poor stars: improved atmospheric parameters and NLTE abundances of magnesium and calcium by Sitnova, T M, Mashonkina, L I, Ezzeddine, R, Frebel, A

“…Abstract The most metal-poor stars are the oldest objects, they provide a unique opportunity to study the earliest epoch of the Galaxy formation and individual…”
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The formation of the milky way halo and its dwarf satellites: a NLTE-1D abundance analysis. IV. Segue 1, Triangulum ii, and Coma Berenices UFDs by Sitnova, T M, Mashonkina, L I, Tatarnikov, A M, Voziakova, O V, Burlak, M A, Pakhomov, Yu V, Jablonka, P, Neretina, M D, Frebel, A

“…ABSTRACT We present atmospheric parameters and abundances for chemical elements from carbon to barium in metal-poor stars in Segue 1 (seven stars), Coma…”
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The formation of the Milky Way halo and its dwarf satellites: A NLTE–1D abundance analysis. V. The Sextans galaxy by Mashonkina, L, Pakhomov, Yu V, Sitnova, T, Jablonka, P, Yakovleva, S A, Belyaev, A K

“…ABSTRACT We present a homogeneous set of accurate atmospheric parameters for a sample of eleven very metal-poor (−3.32 ≤ [Fe/H] ≤−2.61) stars in the Sextans…”
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Non-LTE abundance analysis of A-B stars with low rotational velocities – II. Do A-B stars with normal abundances exist? by Romanovskaya, A M, Ryabchikova, T A, Pakhomov, Yu V, Korotin, S A, Sitnova, T M

“…ABSTRACT We present chemical composition and fundamental parameters (the effective temperature, surface gravity, and radius) for four sharp-lined A-type stars…”
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Evaluation of the Recent Atomic Data for Fe i Lines Based on Solar and Stellar Spectra by Ryabchikova, T., Piskunov, N., Sitnova, T.

“…We performed an extensive comparative analysis of the recent experimental data on Fe  i transition probabilities (TP) based on the observed solar and stellar…”
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Evolution of the titanium and oxygen abundances from observations of FGK dwarfs in a wide metallicity range by Sitnova, T. M.

“…For a sample of dwarf stars close to the Sun with well-known atmospheric parameters and an iron abundance in the range −2.6 < [Fe/H] < 0.2, we have determined…”
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SYSTEMATIC Non-LTE STUDY OF THE −2.6 ≤ [Fe/H] ≤ 0.2 F AND G DWARFS IN THE SOLAR NEIGHBORHOOD. I. STELLAR ATMOSPHERE PARAMETERS by Sitnova, Zhao, G, Mashonkina, L, Chen, Y, Liu, F, Pakhomov, Yu, Tan, K, Bolte, M, Alexeeva, S, Grupp, F, Shi, J-R, Zhang, H-W

“…We present atmospheric parameters for 51 nearby F and G dwarf and subgiant stars uniformly distributed over the -2.60 < [Fe/H] < +0.20 metallicity range that…”
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The Pristine survey – XXII. A serendipitous discovery of an extremely Li-rich very metal-poor giant and a new method of 6Li/7Li isotope measurement by Sitnova, T M, Matsuno, T, Martin, N F, Banerjee, P, Sestito, F, Venn, K A, González Hernández, J I

“…ABSTRACT We report the serendipitous discovery of a very metal-poor (VMP) Li-rich giant star (Teff = 4690 ± 80 K, log g = 1.34 ± 0.13, [Fe/H] = −2.43 ± 0.07)…”
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The Pristine survey – XIX. Cu and Zn abundances in metal-poor giants by Caffau, E, Lombardo, L, Mashonkina, L, Sitnova, T, Bonifacio, P, Matas Pinto, A M, Kordopatis, G, Sestito, F, Aguado, D, Salvadori, S, Spite, M, François, P, Sbordone, L, Mucciarelli, A, Martin, N, Fernández-Alvar, E, González Hernández, J I

“…ABSTRACT Metal-poor stars formed from a gas enriched by the ejecta of the explosion of one/few generations of first massive stars. With the Pristine photometry…”
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Non-LTE Analysis of the Si II Lines in Her with Various Atomic Data Sets by Mashonkina, L., Sitnova, T., Korotin, S.

“…This study shows that the statistical equilibrium of Si II in the atmosphere of a B3 IV type star Her is extremely sensitive to a variation in photoionization…”
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Influence of departures from LTE on calcium, titanium, and iron abundance determinations in cool giants of different metallicities by Mashonkina, L. I., Sitnova, T. N., Pakhomov, Yu. V.

“…We have performed statistical equilibrium calculations for Ca I–Ca II, Ti I–Ti II, and Fe I–Fe II by taking into account the nonequilibrium line formation…”
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The Pristine survey – XIV. Chemical analysis of two ultra-metal-poor stars by Lardo, C, Mashonkina, L, Jablonka, P, Bonifacio, P, Caffau, E, Aguado, D S, González Hernández, J I, Sestito, F, Kielty, C L, Venn, K A, Hill, V, Starkenburg, E, Martin, N F, Sitnova, T, Arentsen, A, Carlberg, R G, Navarro, J F, Kordopatis, G

“…ABSTRACT Elemental abundances of the most metal-poor stars reflect the conditions in the early Galaxy and the properties of the first stars. We present a…”
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