Problems in Stellar Atmospheres and Envelopes [Paperback]

The Energy Flux of the Sun A Critical Discussion of Standard Values for the Solar Irradiance.- 1. Introduction.- 2. High Altitude Experiments.- 3. Discussion of the Results.- 4. Results of Measurements in the Far Ultraviolet.- References.- Model Stellar Atmospheres and Heavy Element Abundances.- 1. Introduction.- 2. The Temperature Stratification.- 3. The Gas and Electron Pressures.- 4. The Energy Distribution in the Continuum.- 4.1. The Balmer Discontinuity.- 4.2. The Ultraviolet Continuum.- 5. The Line Absorption.- 5.1. The Total Line Blanketing.- 5.2. The Metallic Line Absorption.- 5.3. Molecular Lines.- 5.4. The Hydrogen Lines.- 6. The UBV Colors.- 7. The Temperature Calibrations.- 8. The Bolometric Correction.- 9. Convection and Metal Abundances.- 9.1. Convective Instability.- 9.2. Convection Velocities, Microturbulence and Chromospheres.- 9.3. Influence of Convection on the Observed Energy Distribution of Stellar Spectra.- References.- Properties and Problems of Helium Stars.- 1. Introduction.- 1.1. Definitions.- 2. General Properties.- 2.1. List of Objects.- 2.2. Distribution on the Sphere and Velocities.- 2.3. H/He Ratio.- 3. Spectrum.- 3.1. Visual Spectrum.- 3.2. UV-Spectrum.- 4. Atmospheric Structure.- 4.1. Model Atmospheres.- 4.2. Synthetic Spectra and Atmospheric Parameters.- 4.3. Non-LTE Effects.- 5. Individual Obj ects.- 5.1. Extreme Helium Stars.- 5.2. Intermediate Helium Stars.- 5.3. O-Subdwarfs.- 6. Abundances.- 7. Evolution of Model Helium Stars and the (g, Teff) -Diagram.- 7.1. Main Sequences.- 7.2. Evolutionary Tracks.- 7.3. Lifetimes.- 8. Empirical (g, Teff) -Diagram.- 8.1. (g, Teff)-Classification and Masses.- 8.2. Observed Objects.- 9. Variability and Atmospheric Motions.- 10. Conclusion.- References.- Abundance Anomalies in Early-Type Stars.- 1. Introduction.- 2. Problems Related to the Determination of Abundance Anomalies.- 2.1. Definition of Abundances.- 2.2. Relative and Normal Abundances.- 2.3. Model Atmospheres of Peculiar Stars Comparedl£#