Università di Padova


stellar atmospheres
Lecturer: R. Gratton

This course wishes to provide the basis on most important issues concerning stellar atmospheres, and an adequate background to read and understand papers on the most advanced topics in this field.


Introduction to stellar atmospheres and the formation of continuum; basic equations; transfer equation; example cases, initial conditions; Milne problem; atmospheric models; numerical computation of atmospheric models; the absorption coefficient; stability of radiative equilibrium.

Spectral lines; absorbing lines, profiles and equivalent widths; atomic lines, oscillator strengths; damping width and profile; Doppler profile; Stark profile; formation of absortion lines in stellar atmospheres; curve of growth; quantitative chemical analysis; rotational profile.

Convection in 1-d classical models; mixing length approach; 3-d model atmospheres; granulation and convection observational effects; 3-d models for stars; results with 3-d models; limitations of 3-d models.

Structure of the atmosphere and acitivity; photosphere, chromosphere and corona. Solar dynamo. Stellar activity: observations in the optical, UV and X-ray. Connection between activity and rotation. Doppler imaging.

Abundance analysis: examples and applications.