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Centro de Astrofísica da Universidade do Porto

Stellar atmospheres

Giancarlo Pace

Main topics:

  • Radiative processes in stellar atmospheres.
  • Stellar opacities.
  • Modeling of stellar atmosphere.
  • Synthetic spectra.
  • Determination of stellar chemical abundances.
  • Light element abundances and mixing in stars.
  • Magnetic field and non-radiative processes.
  • Stellar dynamo and angular momentum evolution.
  • Stellar chromosphere and chromospheric activity.

I will address the aforementioned topics, dealing with both the physical processes involved and the general astrophysical context. Apart of assuming a background of knowledge in physics and astrophysics common to everybody who will attend the course, I will spend an effort in order to take into account as a broad audience as possible.
The major bibliographical source is: The Observation and Analysis of Stellar Photospheres, by David F. Gray (

Sessão 1: Model atmosphere of a star
17 março 2010

The aim of the first lesson is to give a clear picture of what a stellar model atmosphere is and how it is built. The main physical processes that will be discussed are radiative processes, stellar opacities, and the meaning of termodinamic equilibrium and its local version.

Sessão 2: Line formation and chemical analysis
7 abril 2010

In the second lesson we will analyze more deeply the model atmosphere introduced in the first lesson, reviewing how the stellar parameters (effective temperature, surface gravity and metallicity) affect it. We will then focus on line formation and, finally, we will see how to obtain information on chemical content of a star from its spectrum.