Zdenek Kopal 
Advances in Astronomy and Astrophysics [PDF ebook] 

Advances in Astronomy and Astrophysics, Volume 5 is a collection of papers that deals with the Zodiacal light, three dimensional periodic oscillations, the secular variation of mass, and the evolution of binary systems. Some papers discuss the periodicity of the sunspot groups, as well as compact and dispersed cosmic matter. One paper notes that the brightness of the zodiacal light continues to increase right up to the limb of the Sun, where it merges with parts of the solar corona. Another paper discusses analytically and numerically the three families of three-dimensional motions where the members of each family pass very close to one of three equilibrium points. One paper describes the loss of mass in the Sun as being (1) caused by electromagnetic or corpuscular radiation that occurs at a slow rate, or (2) by an explosion of a nova or supernova. One paper examines the periodicity of solar activities, the physical conditions of sunspots, chromospheric flares, prominence, and magnetic fields. The paper notes that different periodicity laws govern the formation frequency and importance of spot groups. The behavior of spot groups also depends on the periodicity process of solar activity. The collection can prove valuable for astro-physicists, astronomers, geochemists, and mathematicians whose works involve cosmology and astronomy.