Перегляд за Автор "Shavrina, Angelina V."

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  • Ескіз
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    About chemical composition of supergiant PMMR145 in Small Magellanic cloud. Osmium.
    (Astroprint, 2012) Gopka, Vera F.; Shavrina, Angelina V.; Vasilyeva, S. V.; Andrievsky, Serhii M.; Андрієвський, Сергій Михайлович; Андриевский, Сергей Михайлович
    ABSTRACT. The abundance analysis of six Ksupergiants of the Small Magellanic (Hill 1997) showed that the heavier elements (La, Ce, Nd, Eu) have the excess relative to iron [El/Fe]=+0.4 dex, on average, for the sample of five stars (PMMR23, PMMR27, PMMR48, PMMR102, PMMR145). We made the identification of spectral lines in the spectrum of PMMR145 based on the comparison of synthetic and observed spectra. The absorption lines of elements heavier than lanthanides including osmium were identified and abundance of osmium was found ([Os/Fe]=0.59 dex).
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    HIP 13962 - the possible former member of binary system with supernova
    (Одеський національний університет імені І. І. Мечникова, 2016) Yushchenko, V. A.; Yushchenko, A. V.; Gopka, Vera F.; Shavrina, Angelina V.; Kovtyukh, Valery V.; Hong, K. S.; Mkrtichian, D.; A-Thano, N.
    The runaway supergiant star HIP 13962 (spectral type G0Ia) was recently pointed as a possible former binary companion of young pulsar PSR J0826+2637. The spectra of HIP 13962 were obtained in Haute-Provence observatory (France), in Bohuynsan observatory (Korea), and also in NARIT (Thailand) with 1.9, 1.8, and 2.4 meter telescopes respectively. The spectra were obtained in 1995, 2003, 2005, 2014, and 2015. Significant variations of the spectrum are detected. The cores of strong lines show complicated structure, the brightness of the star is variable. The cycles of photometric variations have been changed. We analyzed the spectral observations and present the preliminary chemical composition for elements from iron to lead. The abundance pattern can not be fitted by solar system r- & s-process abundance distribution.
  • Ескіз
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    PRELIMINARY STUDY OF RED SUPERGIANT RM_1-667 IN THE LARGE MAGELLANIC CLOUD
    (Astroprint, 2012) Gopka, Vera F.; Shavrina, Angelina V.; Vasilyeva, S. V.; Yushchenko, A. V.; Yushchenko, V. A.
    The observed lines of hydrogen and another strong lines in the spectrum of RM_1-667 (red region of spectra, 5900-7100 Å, spectral type is K7 I) are discussed. Analysis of these lines indicates the presence of mass outflow from the star at a significant velocity. Using the iron lines and the model atmospheres of supergiants(Teff = 3750 K – 4300 K) of the Kurucz‘ grid, we obtained the iron abundance lg ε (Fe) = 6.75-7.08, which is equivalent to [Fe/H] equal -0.75 to -0.42.
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    Some evolutionary aspects of the binary stellar systems containing neutron star
    (Astroprint, 2012) Ulyanov, Oleg O.; Andrievsky, Serhii M.; Gopka, Vera F.; Shavrina, Angelina V.; Андрієвський, Сергій Михайлович; Андриевский, Сергей Михайлович
    The obvious lack of the binary stellar systems that contain neutron stars (NS) is observed at present. Partly it is caused by the fact that it is very di cult to detect neutron star in a binary system if this relativistic component does not manifest itself as a radio pulsar. Among 1879 pulsars that are listed in the ATNF pulsar catalogue, only 141 pulsars are known to be the companions in binary systems. Only 81 objects having median mass estimation of more than 0.2 M⊙ constitute the binary systems with pulsars. Nevertheless, such systems should be much more numerous and their investigation is of the great interest because thier structure and evolution can certainly help in our understanding of many unique properties that are seen in some stars.
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    Some statistical picture of magnetic CP stars evolution
    (Astroprint, 2010-07) Gopka, Vera F.; Ulyanov, O. M.; Andrievsky, Serhii M.; Shavrina, Angelina V.; Yushchenko, V. A.; Андрієвський, Сергій Михайлович; Андриевский, Сергей Михайлович
    We discuss some statistical results on the evolution of magnetic CP stars in the framework of the supposition about their binary nature.
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    The abundances of heavy elements in red supergiants of Magellanic Clouds
    (Astroprint, 2013) Gopka, Vera F.; Yushchenko, A. V.; Kovtyukh, Valery V.; Shavrina, Angelina V.; Yushchenko, V. A.; Vasilyeva, S. V.; Pavlenko, Y.; Andrievsky, Serhii M.; Андрієвський, Сергій Михайлович; Андриевский, Сергей Михайлович
    ABSTRACT. The spectra of Magellanic Clouds (MC) supergiants PMMR 23, PMMR 144 and RM 1- 667 with resolving power R=30,000 and signal to noise ratio near 100 obtained at 3.6 meter telescope in Chile were analysed. We present a report on the detailed investigation of MC supergiants, with spesial attention to the thorium abundance in these stars. The abundance patterns of three supergiants show that r-process elements are clearly detected in the atmospheres of investigated stars, but the abundances of s-processes elements can vary from star to star.
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    THE NATURE OF MAGNETIC CHEMICALLY PECULIAR STARS PHENOMENON AND THE ORIGIN OF LITHIUM
    (Astroprint, 2012) Gopka, Vera F.; Shavrina, Angelina V.; Yushchenko, A. V.; Yushchenko, V. A.
    According to the modern theory of the evolution of chemical elements their origin seems understandable for most of the elements, from the lightest up to the heavy ones. For element with atomic number Z=3 (lithium) the situation is following: the physical processes and the possible mechanisms of lithium production in stars of different types and ages remain completely unidentified up to now.