Synopses & Reviews
The Sun as now studied is far removed from its early models that described a homogeneous spherical body: chemical fractionation as well as considerable fine-structure in and above the solar surface and internal mixing must now be taken into account. Accordingly, attention in composition studies has shifted from absolute solar abundances toward differences in the chemical (and isotopic) composition of the different parts of the Sun: in its interior, in the structures that make up its atmosphere, and in solar-wind and other, more energetic, particle streams. As was the case with the earlier photospheric composition studies, the investigation of abundance differences results in further clues and input for understanding, in particular, mass-transport, separation and heating mechanisms. This volume contains the reviews and contributions on these topics presented at an ISSI Workshop, and it summarises the resulting discussions in rapporteur papers. The book is intended to provide both active researchers and advanced graduate students with a comprehensive up-to-date `compte rendu' on solar composition.
Synopsis
The discovery of chemical elements in celestial bodies and the first estimates of the chemical composition of the solar atmosphere were early results of Astrophysics - the subdiscipline of Astronomy that was originally concerned with the general laws of radiation and with spectroscopy. Following the initial quantitative abundance studies by Henry Norris Russell and by Cecilia Payne-Gaposchkin, a tremendous amount of theoretical, observa tional, laboratory and computational work led to a steadily improving body of knowledge of photospheric abundances - a body of knowledge that served to guide the theory of stellar evolution. Solar abundances determined from photospheric spectra, together with the very similar abundances determined from carbonaceous chondrites (where extensive information on isotopic composition is available as well), are nowadays the reference for all cosmic composition measures. Early astrophysical studies of the solar photospheric composition made use of atmosphere models and atomic data. Consistent abundances derived from different atmospheric layers and from lines of different strength helped to confirm and estab lish both models and atomic data, and eventually led to the now accepted, so-called "absolute" abundance values - which, for practical reasons, however, are usually given relative to the number of hydrogen nuclei."
Table of Contents
I. Solar Interior. II. Lower Solar Atmosphere. III. Upper Solar Atmosphere and Solar Wind. Author Index. List of Participants.