The Sun as a Variable Star: Solar and Stellar Irradiance Variations: Proceedings of the 143rd Colloquium of the International Astronomical Union held [Paperback]

The IAU Colloquium No. 143 The Sun as a Variable Star: Solar and Stellar Irradiance Variations was held on June 20 - 25, 1993 at the Clarion Harvest House, Boulder, Colorado, USA. The main objective of this Colloquium was to review the most recent results on the observations, theoretical interpreta? tions, and empirical and physical models of the variations observed in solar and stellar irradiances. A special emphasis of the Colloquium was to discuss the results gained on the climatic impact of solar irradiance variability. The study of changes in solar and stellar irradiances has been of high interest for a long time. Determining the absolute value of the luminosity of stars with different ages is a crucial question for the theory of stellar evolu? tion and energy production of stellar interiors. Observations of the temporal changes of solar and stellar irradiances - in the entire spectral band and at different wavelengths - provide an additional tool for studying the physical processes below the photosphere and in the solar- stellar atmospheres. Since the Sun's radiative output is the main driver of the physical processes with? in the Earth's atmosphere, the study of irradiance changes is an extremely important issue for climatic studies as well. Climatic models show that small, but persistent changes in solar irradiance may influence the Earth's climate.Cryogenic Solar Absolute Radiometer  CSAR.- A Review of the Nimbus-7 ERB Solar Dataset.- Long-Term Variations in Total Solar Irradiance.- Solar Total Irradiance Variability from SOVA 2 on Board EURECA.- The Periodicity of Solar Activity Cycles.- Maximum and Minimum Temperatures at Armagh Observatory, 18441992, and the Length of the Sunspot Cycle.- Photometer DIFOS for the Study of Solar Brightness Variations.- The Brightness of the Solar Disk in the Continuum in the Region 1.02.4 ?m.- Irradiance Observations of the 18 ? Solar Soft X-Ray Flux from GOES.- Comparisons of the Mg II Index Products from the NOAAlÃ'