AST 383C Stellar Atmospheres Spring 2009 MWF 11 00 12 00 RLM 15 216B Unique No 48580 LEVEL B hm Vitense Introduction to Stellar Astrophysics Volume 2 Stellar Atmospheres Mihalas Stellar Atmospheres Gray Observations and Analysis of Stellar Photospheres Rybicki and Lightman Radiative Processes in Astrophysics SYLLABUS I II III IV V VI VII VIII IX Summary of Observational Data Motivations for studying stars Spectral and luminosity classification Relation of theory and observation Elements of Radiative Transfer Theory Definitions Emission absorption and scattering Equation of transfer radiative equilibrium Gray Atmospheres Milne s equation Two stream and Eddington approximations Emergent flux and limb darkening Local Thermodynamic equilibrium LTE Elements of statistical mechanics Perfect gases and the Saha equation Conditions for LTE Depression of the adiabatic gradient in a partial ionization zone Non LTE Rate Rate equations Radiative and collisional rates departure coefficients Calculation of Einstein coefficients and collision cross sections Continuum Opacity Opacity sources in high intermediate and low temperature stellar atmospheres LTE Continuum model Atmospheres Basic equations Numerical solution of transfer equation iteration Kurucz s and Feautrier s methods Temperature correction procedures Results and Comparison With Observations Absolute energy distributions The Balmer jump Sample model atmosphere calculation Flux distributions for sample model stars Effect of absorption edges on atmospheric structure line blanketing molecule formation Mixing Length Theory Convection and partial ionization zones Simple phenomenological models X XI XII Line Spectra Line absorption profiles Natural broadening and the Lorentz profile Doppler broadening and the Voigt profile Collisional broadening Stark broadening Inglis Teller formula Line Transfer Problem Line transfer equation pure scattering lines and pure absorption lines Center to limb variations Schuster mechanisms Curve of growth and abundance determinations Model atmosphere line calculations Line blanketing theory LTE line formation Moving Atmospheres Modeling stellar atmospheres with winds require hydrodynamic NLTE treatment Development of a first principles approach to the problem Applications to Hot stars