| Abstract [eng] |
In the Thesis, the influence of convection and non-equilibrium radiative transfer on the structure of stellar atmospheres and spectral line properties is investigated. State-of-the-art three-dimensional hydrodynamical model atmospheres are used to study the role of convection in the formation of spectral lines of neutral iron in the metal-poor red giant HD 122563, as well as its impact on the formation of spectral lines of light elements (Li, Na, Mg, Al, K, Mg, Ca) in the atmospheres of red giant stars. The influence of convection on the spectral line properties increases with decreasing metallicity of the star: in red giants, abundance corrections for the light elements do not exceed 0.1 dex at solar metallicity while at [M/H] = –3.0 corrections reach up to –0.7 dex. Convection and non-equilibrium radiative transfer have a significant impact on the strength and shape of Li I 670.8 nm resonance doublet. The latter effect is most pronounced in solar metallicity red giants where 3D NLTE – 1D LTE abundance corrections reach up to +0.3 dex, while for the main sequence and subgiant stars these corrections do not exceed +0.2 dex. In the Thesis, methodical techniques and abundance corrections are provided which can be used in the future studies to determine 3D NLTE Li abundance in the atmospheres of main sequence, subgiant and red giant stars. |
