Перегляд за Автор "Gorbaneva, Tatyana I."
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Документ Abundances of neutron-capture elements in red giant stars(Madrid : Consejo Superior de Investigaciones Científicas, Instituto Miguel Asín,, 2007) Gorbaneva, Tatyana I.The neutron-capture element abundances in the 52 red giants with metallicities spanning the range −0.6 < [Fe]/[H] < 0.25 are found. High-resolution spectra (R = 42000; S/N > 100) for the investigated stars were obtained with the ELODIE spectrograph of the 1.93m telescope at the Observatoire de Haute Provence (France). The determination of elemental abundances was carried out with the local thermodynamic equilibrium assumption by the model atmosphere method; for Ba and Eu the hyperfine structure was taken into account. The dependences of the neutron-capture element abundances on metallicity are presented.Документ EU ABUNDANCES IN ACTIVE AND NON-ACTIVE STARS(Astroprint, 2010-07) Gorbaneva, Tatyana I.; Mishenina, T. V.Eu abundances have been determined for stars observed at high resolution, high signal to noise ratio with the ELODIE spectrograph at the 1.93-m telescope of the Observatoire de Haute Provence(France). Among them more than 30 stars are active stars with a fraction of BY Dra and RS CVn type stars for which spectral pecularities were investigated. For all stars fundamental parameters were determined earlier. We nd the mean abundances of the majority of elements in active and non-active stars. Active and non active cool dwarfs show similar dependencies of elemental ratios vs [Fe/H].Документ Hafnium abundances in fgk dwarf of galactic disk(Одеський національний університет імені І. І. Мечникова, 2018) Gorbaneva, Tatyana I.; Mishenina, T. V.; Горбаньова, Тетяна І.; Мишенина, Т. В.In this work we present new observational data for hafnium (72). Hf is an important element that is between the lightest rare-earth elements (e.g., La, Z = 57) with elements of the third r-process peak (Os, Ir, Pt, Z =76-78). Hafnium is the heaviest (Z = 72) stable element represented by low-excitation (<1:5 eV) ionized lines in the spectra of the cool stars (Lawler et al., 2007). This element is important as a stable reference element for nucleocosmochronometry, and also to study of the sources of its production and enrichment with n (neutron)-capture elements of Galactic disc. We provide the analysis of the spectra of 126 FGK dwarfs in metallicity range from −1.0 < [Fe/H] < +0.3 that were taken from our starting sample of 276 stars (Mishenina et al. 2013). The observed stars belong to the substructures of the Galaxy disc. The observations were conducted using the 1.93 m telescope at Observatoire de Haute-Provence (OHP, France) equipped with the echelle type spectrographs ELODIE and SOPHIE. The results are based on analyses of spectra that have a typical S/N ~ 100-300 and a resolution of 42 000 (ELODIE) and 75 000(SOPHIE). The hafnium abundance was derived by comparing the observed and synthetic spectra in the region of two Hf II line (λ4080.437 Å and λ4093.155 Å), making use of the LTE approximation. The obtained hafnium abundance decrease with increasing metallicity in both discs, and have a big scatter at all metallicities. The dependence of our Hf abundance on metallicity and their comparison with those of other authors is presented. It corresponds to typical behavior of the elements behind the iron peak, the elements formed in the processes of neutron capture. The sources of the Hf enrichment of Galactic disc are considered.Документ MANGANESE ABUNDANCES IN THE ATMOSPHERE OF CLUMP GIANTS(Astroprint, 2013) Gorbaneva, Tatyana I.ABSTRACT. The manganese abundances was determined in the atmospheres of clump giants stars whose selection was made earlier based on their chemical composition and evolutionary tracks. The spectra of the studied stars were obtained using the facilities of the 1.93 m telescope of the Haute-Provence Observatoire (France) equipped with the échelle spectrograph ELODIE (R = 42000, S/N = ~100–300). The Mn abundances was determined under the LTE approximation by the synthetic spectrum approach with a detailed consideration of the superfine structure. The behaviour of manganese abundances with metallicity [Fe/H] was considered.Документ Molybdenum abundance in some open clusters(Одеський національний університет імені І. І. Мечникова, 2018) Shereta, E. P.; Carraro, G.; Gorbaneva, Tatyana I.; Mishenina, T. V.; Шерета, Е. П.; Карраро, Ж.; Горбаньова, Тетяна І.; Мишенина, Т. В.This paper presents the results of determination of the molybdenum abundances in 13 G, K type stars in the open clusters NGC 2477 and NGC 2506. The abundances of molybdenum were determined using stellar atmosphere models by Castelli & Kurucz (2004), as well as a modified STARSP LTE spectral synthesis code (Tsymbal, 1996). For the used Mo I lines 5506 and 5533 Å the oscillator strengths log gf were adopted from the latest version of the VALD database dated 2016 (Kupka et al., 1999). The high resolution spectra were obtained with a VLT telescope at the European Southern observatory (ESO, Chile). We used atmospheric parameters of the investigated stars which we had obtained earlier. We have found out that the molybdenum abundances depend on metallicity [Fe/H] in giants of NGC 2506 and NGC 2477. For the stars in NGC 2506, molybdenum is slightly overabundant as compared to the solar abundance; such an overabundance is slightly higher in the stars of the second investigated cluster NGC 2477. Further investigation of the Mo abundance in larger number of open clusters is required to draw reliable conclusions.Документ Molybdenum and Ruthenium abundances in Cool stars of the Galactic DISC(Одеський національний університет імені І. І. Мечникова, 2017) Gorbaneva, Tatyana I.; Mishenina, T. V.We revise the molybdenum and ruthenium abundances in FGK stars with metallicities ranging from −1.0 < [Fe/H] < +0.3. The observed stars belong to the substructures of the Galaxy. The observations were conducted using the 1.93 m telescope at Observatoire de Haute-Provence (OHP, France) equipped with the echelle type spectrographs ELODIE and SOPHIE. The results are based on analyses of spectra that have a typical S/N ~ 100-300 and a resolution of 42 000. These estimates were obtained using synthetic spectra computed with LTE model atmosphere.Документ Molybdenum and ruthenium in the Galaxy(Одеський національний університет імені І. І. Мечникова, 2018) Mishenina, T. V.; Gorbaneva, Tatyana I.; Мишенина, Т. В.; Горбаньова, Тетяна І.We present a brief overview of the molybdenum and ruthenium present-day nucleosynthesis calculations and abundance determinations in stars belonging to different substructures (populations) in the Galaxy. The following sources of Mo, Ru production were considered: the Asymptotic Giant Branch (AGB) stars of different masses (main s-process), massive stars (weak s-process), neutrino-induced winds from the core-collapse supernova CCSNe (weak r-process), merging of neutron stars (main rprocess). Many production sites of the p-nuclei have been proposed: the Type II and Ia supernovae (at the presupernova phase, during and after the supernova explosion), the rp-process in neutrino-driven winds, the high-entropy wind (HEW), the νp-process; inside in a supercritical accretion disk (SSAD), in the He-accreting CO white dwarfs of sub-Chandrasekhar mass, and in the carbon deflagration model for Type Ia. We also emphasize on some additional processes such as the i- process in rapidly accreting white dwarfs (RAWDs), the lighter element primary process LEPP as well as another formation channel, namely the charged-particle process (r- process). The contribution to the solar abundance of neutron capture elements and the Galactic Chemical Evolution (GCE) models for n-capture elements were considered. The Mo and Ru observations in metal-poor stars, Ba stars, globular clusters, meteoritic matter (presolar grains) as well as our new Mo and Ru determinations in Galactic disc are presented. Having analysed our date in the near solar metallicities we found out that there are different sources contributing to the Mo and Ru abundances, and that the main s-process contribution to the Mo and Ru abundances is lower than to the predominant s-element (Y, Zr and Ba) solar abundances. By comparing the behavior of Mo and Ru in the wide range of [Fe/H] with GCE models one can see that the theoretical description of the galactic behavior of Mo not depicts sufficient and we are faced with the underproduction of molybdenum in the sources and in processes that used at the GCE creation. Additional sources may be the p-process (SN Ia and/or SN II), νp-process (massive stars) or several more exotic processes.Документ Strontium abundances in cool dwarf stars of galactic thin and thick disks(Одеський національний університет імені І. І. Мечникова, 2016) Gorbaneva, Tatyana I.; Mishenina, T. V.We revise the strontium abundances in FGK stars with metallicities ranging from −1.0 < [Fe/H] < +0.3. The observed stars belong to the substructures of the Galaxy thick and thin discs. The observations were conducted using the 1.93 m telescope at Observatoire de Haute-Provence (OHP, France) equipped with the echelle type spectrographs ELODIE and SOPHIE. The values of the Sr abundance were obtained using synthetic spectra using LTE model atmosphere. The comparison of our data with models of chemical evolution was made.Документ Strontium abundances in cool dwarf stars of galactic thin and thick disks(Одеський національний університет імені І. І. Мечникова, 2016) Gorbaneva, Tatyana I.; Mishenina, T. V.We revise the strontium abundances in FGK stars with metallicities ranging from −1.0 < [Fe/H] < +0.3. The observed stars belong to the substructures of the Galaxy thick and thin discs. The observations were conducted using the 1.93 m telescope at Observatoire de Haute-Provence (OHP, France) equipped with the echelle type spectrographs ELODIE and SOPHIE. The values of the Sr abundance were obtained using synthetic spectra using LTE model atmosphere. The comparison of our data with models of chemical evolution was made.