Stellar Atmospheres


an advanced course (10 credits)

at the Astronomy research unit, University of Oulu

The course period: September 4 – December 20, 2019

Lectures, exercise and practical sessions take place usually on Wednesday at 14-16 and Friday at 12-14, see WebOODI for detail.

The course is lectured in English

Teacher: Vitaly Neustroev, MA 302, vitaly[-at-]neustroev.net


Course plan:

  • Radiation terms and definitions
  • Stellar photospheres
  • Stellar atmospheres
  • Stellar winds
  • Interstellar Medium
  • Accretion discs
  • etc…

Theoretical and practical considerations will be supplemented with the home exercises which constitute the important part of the course.



  • Lecture 1: September 4: Introduction (What is a stellar atmosphere? Spectral Types, Luminosity Classes, Magnitudes, Bolometric Flux and Bolometric Correction)
  • Lecture 2: September 6: Basics about radiative transfer (Radiation terms, Specific and mean intensity, Flux & luminosity, Black body radiation (Planck function), Effective temperature (Stefan-Boltzmann law), Brightness and Color temperatures)
  • Lecture 3: September 11: Basics about radiative transfer (radiation density and pressure), Interaction radiation – matter, Parallel-Ray transfer equation.
  • Lecture 4: September 13: Radiative transfer (Radiative transfer equation in plane-parallel atmosphere. Limb darkening), Solution to transfer equation, Eddington-Barbier relation. Grey atmosphere.
  • Lecture 5: September 18: Grey atmosphere. Radiative equilibrium. The depth dependence of the source function. Eddington approximation. Temperature structure of the grey atmosphere.
  • Lecture 6: September 20: LTE (Maxwellian distribution in velocities, Boltzmann equation, Saha formula).
  • Compulsory problems: [Set 1] (return by October 2).
  • Lecture 7: October 2: Stellar Opacity (Bound-bound, bound-free and free-free absorptions).
  • Lecture 8: October 4: Other sources of opacity (H-, He and Metallic absorptions, Scattering, Effect of nongreyness of the temperature structure).
  • Lecture 9: October 9: Rosseland mean opacity, Towards the Model Photosphere (Hydrostatic equilibrium, Gas Pressure, Electron Pressure).
  • Lecture 10: October 11: Towards the Model Photosphere (Radiation pressure, Eddington limit).
  • Compulsory problems: [Set 2] (return by October 16 [Problem 3 is revised, return by October 30, 14:15]).
  • Lecture 11: October 16: The Forgotten Chapters (Radiation, Astrophysical, and Eddington Flux; Wavelength dependence of absorption coefficients; Balmer jump).
  • Compulsory problems: [Set 3] (return by October 30, 14:15).
  • Mid-term exam: October 30.
  • Lecture 12: November 1: Spectral lines (EQUIVALENT WIDTH Equivalent Width, FWHM, FWZI, Radial Velocity).
  • Practical Session: November 6: Software (Iraf, Dech).
    Spectra of stars: Vega, Sun