Lyubchik Y. Modeling of the late-type stellar spectra

The Thesis is devoted to the late-type stellar spectra modeling. It was shown that we can use simplified techniques of computations of molecular opacity to fit late-type stellar spectra of low and medium resolution. "Line by line" molecular opacity approximation is necessary to fit to the high resolution spectra. Calculations of synthetical spectra with Plez's(1998) and Schwenke's(1998) TiO linelists provide almost identical results. In the work observed spectra of the two binary stars of F, G spectral types were fitted to determine abundances of Li, Fe, Al, Si, Ca. Energy distributions in spectra of late M-dwarfs GJ1111(M6.5V) and GJ51(M5V) and brown dwarf Teide1(M8) were calculated. We confirm the possibility of our spectra modeling technique for fitting to substellar objects spectra. The spectra of two pre-main sequence stars V927 Tau(M5.5IV) та FN Tau(M5IV) were modeled to determine lithium abundances in their atmospheres.