Aryana Libris

Author : Gershberg Roald Evgenevich
Title : Solar-type activity in main-sequence stars
Year : 2005

Link download : Gershberg_Roald_Evgenevich_-_Solar-type_activity_in_main-sequence_stars.zip

Preface. Over the last decades our insight into the realm of stars was deepened considerably by many outstanding discoveries: pulsars, neutron stars predicted in the 1930s; discrete X-ray sources, stellar systems with much stronger X-ray emission than optical luminosity; maser emission related to the early stage of stellar evolution and to some oscillating supergiants that have reached an advanced evolutionary stage; intense outflow of matter from hot stars, etc. Parallel to these discoveries, which are mainly due to progressing methods of astrophysical observations, the comprehension of many stellar events improved markedly. The spectra of supernovae were successfully interpreted and the hydrodynamic theory of flares on them was elaborated. The theory of stellar evolution in binary systems yielded the concept of mass exchange as a decisive factor of their evolution and gave a key to understanding the activity of a wide family of novae, symbiotic and cataclysmic systems. As a result of the development of the evolution theory of early spectral-type stars, oscillating cepheids – the lighthouses of the Universe that were used to determine distances to different stellar systems – had become space-time references of the development of such systems. As compared to these impressive findings for extremely interesting but rather rare types of stars, which attract the attention of astronomers of all specialties and not only astronomers, the study of very faint and cool variable dwarfs – UV Cet-type flare stars – might seem too narrowly specialized. However, successful investigation of these stars changes essentially the general concepts of the “stellar kingdom”. During the last decades it became clear that, first, flare dwarfs make up the most abundant type of stars and, secondly, their activity, being of the same physical nature as solar activity, plays a major role among lower main-sequence stars. ...