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Information × Registration Number 0212U006203, 0109U008875 , R & D reports Title Chemical composition of B-, A-and G-stars of different luminosity classes popup.stage_title Head Lyubimkov Leonid S., Registration Date 01-03-2012 Organization Scientific-research institute "Crimean asrophysical observatory" popup.description2 The lithium abundance in atmospheres of 43 F- and G-type supergiants and bright giants is analyzed. For the first time a rather complete comparison of the derived Li abundances with predictions of the theory is implemented. New computations of evolutionary stellar models with masses M from 2 to 15 Mo are used here (both with and without rotation). Both the theoretical computations and the obtained data show that the stars in question can be separated according their Li abundances into two groups depending on their masses M, namely M < 6 Mo and M > 6 M0. In particular, it is shown that all known Li-rich stars, where log ?(Li) ? 2.0, have masses M < 6 Mo. Most of the results are in good agreement with predictions of the theory; in particular, an absence of detectable lithium for the majority of programme stars is explainable. However, for some stars their high Li abundance contradicts the theory. In this case the freshly produced lithium is likely to be observed. An analysis of large spectral data for the magnetic CP star HD 3980 is implemented. Spectral lines of 13 chemical elements are studied by the Doppler Imaging method; rotational variability of the line profiles is considered. A map of the lithium distribution on a surface of the star HD 3980 is obtained. It is shown that there are two lithium spots on its surface, which are located in regions of magnetic poles. Thus, one more magnetic rapidly-rotating star with lithium spots on the surface is discovered. Product Description popup.authors Любимков Леонид Сергеевич Поклад Дмитрий Борисович Полосухіна-Чуваєва Ніна Савельївна Рачковская Тамара Михайловна Смірнова М.О. popup.nrat_date 2020-04-02 Close