Перегляд за Автор "Basak, N. Yu."

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    ANALYSIS OF THE PARAMETERS AND ABUNDANCE OF N-CAPTURE ELEMENTS FOR FOUR STARS WITH DIFFERENT METALLICITY
    (Astroprint, 2013) Basak, N. Yu.; Mishenina, T. V.
    ABSTRACT. Based on the spectra obtained with echelle spectrograph SOPHIE (1.93 m telescope, OHP, France) and the selection of lines (Basak & Mishenina, 2012). we have redefined the parameters and have determined the abundances of the elements produced in the process of neutron captures for stars HD 6582, HD19445, HD 84937, HD170153. Obtained abundance of Y, Zr, La, Ce, P, Nd, Sm, and Gd,shows the solar scaled abundance distribution.
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    Chemical imprints in atmospheric abundances in planet- hosting stars
    (Одеський національний університет імені І. І. Мечникова, 2019) Mishenina, T. V.; Basak, N. Yu.; Kovtyukh, Valery V.; Мишенина, Т. В.; Басак, Н. Ю.; Ковтюх, Валерій В.
    We examined 12 planet-hosting stars based on homogeneous spectral data (obtained with the SOPHIE echelle spectrograph with R = 75,000 at the OHP, France) and using uniform techniques for determination of parameters and abundances of a series of elements (Li, C, Na, Mg, Al, S, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Ba, La, Ce, Pr, Nd, Sm and Eu). For our set of stars with detected massive planets, we have found [Fe/H] ranging from --0.3 to 0.4 dex. There is the only star for which the lithium content has been reliably shown to be lower than predicted values. Average C/O ratio (0.52±0.08) is slightly lower than the solar one (0.54), and C/O ratios tend to correlate with the planetary mass. Magnesium follows the trend in Galactic chemical evolution exhibiting a dependence on the planetary mass. Manganese and barium are both slightly overabundant.
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    LINES SELECTION TO DETERMINE THE CHEMICAL COMPOSITION OF STARS IN THE RANGE -3 ≤ [FE/H] ≤ -0.7
    (Astroprint, 2012) Basak, N. Yu.; Mishenina, T. V.
    ABSTRACT. Using the spectra obtained with echelle spectrograph SOPHIE (1.93 m telescope, OHP, France)and the data from about 20 papers of various authors, we have compiled a list for around four thousand lines of different chemical elements. Based on the spectra of the Sun and stars and also synthetic spectrum calculations in different ranges of metallicity, we selected 300 unblended lines of FeI, FeII and 200 lines of YII, ZrI, ZrII, LaII,CeII, PrII, NdII, SmII, GdII, that are recommended for thestudy of the chemical composition.
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    n-CAPTURE ELEMENTAL ABUNDANCES IN ACTIVE AND NON-ACTIVE STARS
    (Astroprint, 2010-07) Basak, N. Yu.; Mishenina, T. V.; Soubiran, C.; Kovtyukh, Valery V.; Belik, S. I.
    Abundances of Y, Zr, La, Ce, Nd, and Sm have been obtained under LTE approximationss. The program stars were observed at high resolution, high signal to noise ratio with the ELODIE echelle spectrograph (OHP, France). Among them more than 30 stars are active stars with a fraction of BY Dra and RS CVn type stars. Comparison of the behavior of n-capture elemental abundance in active and non active stars was made.
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    Three giants – members of The Open cluster M 67
    (Одеський національний університет імені І. І. Мечникова, 2017) Mishenina, T. V.; Klochkova, V. G.; Panchuk, V.; Basak, N. Yu.; Kovtyukh, Valery V.; Korotin, S. A.; Velichko, A.
    We determined the atmospheric parameters and chemical composition of the three giants, which are members of the open cluster M 67. The high resolution spectra (R = 60 000) were obtained with the echelle spectrograph NES mounted on the 6-meter telescope of the SAO RAS Obtained variations in Na and Zr abundances are within the determination errors. The Li abundance suggest a depletion of Li in the course of stellar evolution. For studied giants, the iron abundances derived from the neutral and ionized iron lines have not shown any significant discrepancies. The [Ba/Fe] values are close to the solar ones.