The Chemical Composition of the Sun

The paper reviews procedures used in determining the solar chemical composition and, by inference, the original chemical composition of the solar system. The spectrum-synthesis method for analyzing the photospheric absorption spectrum is described in detail, determination of the chromospheric and coronal abundances is discussed, and the use of solar-wind data to obtain abundance estimates is noted. The elements whose solar abundances have been determined or estimated are listed in a table which also includes the quality of the determination, the solar system abundance (as derived mostly from carbonaceous chondrites), and the source of the solar data (e.g., photospheric absorption lines, chromospheric observations). The problem of determining the solar helium and iron abundances is examined, and note is taken of the need for improved experimental data and theoretical models.