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Introduction to modeling of stellar and planetary atmospheres; radiative transfer equation and its numerical
solutions; models of atmospheres, magnetohydrodynamics and equilibrium in atmospheres; physical processes
in atmospheres of different stellar types, planets and accretion discs. Two-level model of atom, numerical solution
of the radiation transfer equation.
Last update: Vokrouhlický David, prof. RNDr., DrSc. (10.01.2019)
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The oral part consists form one question relating to the theory of stellar atmospheres and one to the physical processes in the stellar and planetary atmospheres, or accretion discs. The discussion about a chosen paper is also a part of the exam.
Last update: Korčáková Daniela, doc. Mgr., Ph.D. (07.06.2019)
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Hubený, I. & Mihalas, D. Theory of Stellar Atmosheres, Princeton University Press, 2015 Lamers, H.J.L.M, Introduction to Stellar Winds, Cambridge University Press, 2012 Michaud, G., Alecian, G., Richer, J. Atomic Diffusion in Stars, Springer, 2015 Mihalas, D., Stellar Atmospheres, W. H. Freedman and Company, 1978 Mihalas, D. & Mihalas, B.W., Foundations of Radiation Hydrodynamics, Oxford University Press, 1984 Rutten, R.J., Radiative Transfer in Stellar Atmospheres, Lecture Notes Utrecht University, 2003 Last update: Vokrouhlický David, prof. RNDr., DrSc. (10.01.2019)
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Přednáška. Last update: T_AUUK (31.03.2008)
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A student has to be prepared for the discussion about the article, which she/he will choose from the list given at the beginning of the semester. Last update: Korčáková Daniela, doc. Mgr., Ph.D. (07.06.2019)
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Theory of stellar atmospheres
Characterising radiation fields: specific intensity, flux, energy density, Maxwell equations, radiation pressure tensor, opacity, emissivity, optical depth, scattering, photon mean free path. Radiative transfer equation: formulation, moments, diffusion approximation, boundary conditions, formal solution, numerical solutions - Feautrier method, short characteristic method, long characteristic method, discontinuous finite element method, Monte Carlo method. Radiative transfer equation in moving media - Lorentz transformation, radiative transfer equation in the observer frame, in the comoving frame, Sobolev method. Grey atmosphere, Rosseland mean opacity, Planck mean opacity, Milne relations, Eddington solution. Einstein coefficients, Planck law, Einstein relations, classical oscillator, cross sections, oscillator strengths, Gaunt factors, opacity, negative ion of hydrogen, electron scattering, Rayleigh scattering, Boltzmann equation, Saha equation, state equation, thermodynamic equilibrium, local thermodynamic equilibrium, non-LTE, radiative rates, collisional rates, equation of statistical equilibrium. Models of stellar atmospheres Line broadening - natural broadening, pressure broadening, thermal broadening, Voigt function, Holtzmark theory, Milne-Eddington model, limb darkening, gravity darkening. Physical processes in individual objectsPhysical processes in stellar atmospheres: convection - convective equilibrium, semi-convection, thermohaline convection; pulsations; element segregation - diffusion equation, settling, radiative levitation; stellar winds - isothermal winds, non-isothermal winds, coronal winds (see solar physics), dust driven winds, line driven winds, Alfvén wave driven winds (see solar physics). Planetary atmospheres and atmospheres of brown dwarfs: terminology astronomy vs meteorology, processes in planetary atmospheres, types of giant planets, standard model, numerical models. Atmospheres of individual stellar types: pre-main sequence stars, main sequence stars, WR stars, white dwarfs, neutron stars, accretion discs, novae. Last update: Vokrouhlický David, prof. RNDr., DrSc. (10.01.2019)
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