Course required for degree Diploma in Astrophysics.
VII Semester 2+2, VIII Semester 2+2

INTRODUCTION. Theory and Problems in Stellar Structure and Evolution. Observed Physical Characteristics of Stars. Empirical Relations and Diagrams.

DESCRIPTION OF STELLAR INTERIORS - PHYSICAL PRINCIPLES. General Distribution Law of Matter. Distributions of Gas Particles and Photons in Statistical Equillibrium. Conditions for LTE. Degenerate States. Simple Perfect Gas and Black Body Radiation. Free Electron Density. Mean Molecular Weight. Radiation Field Parameters. Equation of State. Polytropic Processes. Adiabatic Changes. Some Thermodynamic Relations. Absorption Mechanisms and Processes under Typical Conditions in Stellar Interiors. Monochromatic Mass Absorption Coefficients: Bound-Free and Free-Free Transitions. Scattering on Free Electrons. Total Opacity. Rosseland Mean Opacity. Approximate Formulae. Kramers' Law. The Influence of Heavier Elements on the Opacity. Energy Transfer. Thermal (Energetic) Equilibrium. Radiative equilibrium. Energy Flux in Radiative Equilibrium. Thermal Conduction. Convective Equilibrium. Temperature Gradients in the Convective Zone. Average Speed of Convecting Elements. Conditions for Turbulence to Appear. Convective Flux and Methods for its Computation. Stability of Transfer Mechanisms. Stellar Energy Sources. Thermonuclear Reactions. Hydrogen and Helium Burning Reactions. Heavier Isotopes Burning Reactions. Energy Production Rate. Approximate Formulae. Neutrino Energy Losses. Gravitational Potential Energy of a Star. Conditions for Gravitational Contraction. Local Energy Release from Gravitational Contraction. The Virial Theorem. Internal and Total Energy of a Star. Dynamical Stability.

STELLAR MODELS AND EVOLUTION. Hydrostatic (Gravitational) Equilibrium for Spherical Symmetry. Integral Theorems for Equilibrium of Stars. Vogt-Russell Theorem. Formal-Mathematical Proof. Physical Interpretation. Analytical Models. Polytropic Stars. Standard Model. Uniform Energy Source Model. Point-Source Model. Stellar Envelopes in Radiative Equilibrium. Convective Stellar Envelopes. Temperature Distribution in the Envelope (Problems). Computation of Stellar Models. Equations of Structure. Boundary Conditions. Dimensionless Variables. Transformations for Integration from the Surface. Variables for Integration from the Center. Invariants and the U-V Plane. Numerical Integration. Schwarzschild Technique. Henyey Technique. Hydrodynamic Technique. Variable Chemical Composition. Basic Phases of Stellar Evolution. Initial Phase (The Jeans Instability, Formation and Evolution of Proto-Stars, Hayashy Sequences , Zero-Age Sequence). Main Sequence Phase (Evolution Rate Depending on Mass, Main Sequence Theoretical Limits, Global Structure of Hot and Cold Stars). Evolution of Massive Stars After the Main Sequence (Thermal Instability, Gravitational Contraction of Central Core, Hydrogen Reactions in the Stellar Envelope, Red Giant Stage - Spending of Helium in the Central Core, Hydrogen and Helium Burning Reaction in Stellar Envelopes, Pulsational Instability). Final Stages (Conditions for Dynamical Instability: Planetary Nebula, Supernovae - White Dwarfs, Neutron Stars, Black Holes). Developing Sequences of Models. Evolution with Variable Mass. Homologous Models. Time Scales of Evolution. Gravitational Collapse. Dynamical Expansion. Heating and Cooling. Kelvin's Scale. Scale of Nuclear Evolution. Evolution of Chemical Elements. Contemporary Composition of Interstellar Matter. Heavy Elements Production in Supernovae Explosion. Young and Old Stars.

EXERCISES. Theoretical and Computational Exercises.

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