This book introduces the theory of stellar atmospheres. Almost everything we know about stars is by analysis of the radiation coming from their atmospheres. Several aspects of astrophysics require accurate atmospheric parameters and abundances. Spectroscopy is one of the most powerful tools at an astronomer's disposal, allowing the determination of the fundamental parameters of stars: surface temperature, gravity, chemical composition, magnetic field, rotation and turbulence. These can be supplemented by distance measurements or pulsation parameters providing information about stellar interior and stellar evolution, otherwise unavailable.
The volume is based on lectures presented at the Wroclaw's Spectroscopic School aimed at training young researchers in performing quantitative spectral analysis of low-, mid-, and high-resolution spectra of B, A, and F-type stars.

Contenu
Introduction.- Stellar Atmospheres: basics processes and equations.- How to build a model of the atmosphere and spectrum.- Atomic data - where to get them, how to use them.- Problems with atomic and molecular data: including all the lines.- Spectral classification: The first step in quantitative spectral analysis.- Effective temperature determinations.- How to determine surface gravity from spectrum and spectral lines.- Stellar parameters from photometry.- Spectral lines analysis: rotational velocity and velocity fields.- Convection and turbulence.- Diffusion and its manifestation in stellar atmospheres.- Magnetic fields.- Chemically peculiar stars.- Spectroscopic analysis of cool giants and supergiants.- Basics of the NLTE physics.- Analysis of stellar spectra with 3D and NLTE models.- NLTE analysis of spectra: OBA stars.- Current status of NLTE analysis and perspectives for future.- What influences the results?.- Solar abundances problem.- Spectral synthesis codes and methods of analysis.- Model Atmosphere Codes: ATLAS12 and ATLAS9.- A gentle introduction to the SME.- ARES+MOOG a practical overview of an EW method.