The course is offered to students of any study field.
The main objectives of the course is the understanding of the structure of inner parts of the stars, stellar atmospheres, and evolution.
The definition of astrophysics. The main building blocks of our Universe. The parameters of our Sun and their relationship with other star. Stellar parameters. A typical star in the solar neighbourhood.
The selection effect.
Definition of stars, models. Mechanical equilibrium in star. Estimate of the central pressure. Physical state of the matter in the star, high-temperature plasma. Thermodynamic equilibrium. Why do stars radiate? Stellar contraction.
Ideal gas. Estimate of the central stellar temperature. Electromagnetic radiation, its characteristics, and its origin. Black body radiation. Photon gas. What is the origin of solar photons?
Thermonuclear reactions and its role in the stellar energetics. Nucleosynthesis. Energy equilibrium. Radiative diffusion. Opacity and its sources.
The dependence of the characteristics and life time on mass. Stellar structure equations. The origin of the stellar evolution.
First ideas of the stellar nature. The benginning of the stellar spectroscopy and astrophysics.
The nature of the stellar atmospheres? What is the evidence about their existence?
Atomic structure. Hydrogen atom structure. Energy levels. Excitation and deexcitation. Spectrum of hydrogen and hydrogen-like atoms. The nature of spectral series. Structure and spectrum of more complex atoms. Bound-free and free-free transitions and its effect on the spectrum. Interaction of atoms with radiation. Radiation of dense and tenuous gas. Why do star radiate similar to black body?
The origin of spectrum in the stellar atmosphere. Continuum and line transitions. Line profiles and their broadening. Model stellar atmospheres.
Ionization and excitation in the stellar atmospheres. Boltzmann and Saha equation. The dependence of spectrum on temperature and pressure. Spectral classification.
Solar atmosphere. Photosphere, chromosphere, corona, and solar wind.
General characteristics of the stellar evolution (example of our Sun).
Formation of stars. Evolution up to T Tauri stage. The evolution of the stellar core till the end of the main sequence.
The late phases of the evolution of the stellar core.
The electron degeneracy and its role in the stellar evolution. Mass loss and its role.
Evolution of our Sun till the present times. Structure of present Sun.
Expected future evolution of our Sun. The evolution of ideas on the formation and evolution of Sun and stars.
The definition of the late stages of the stellar evolution. List of possible evolutionary paths. The degenerate gas. Equation of state of cold catalysed matter. Neutron stars. Black holes.