Relative Coronal Abundances Derived from X-ray Observations III: The Effect of Cascades on the Relative Intensity of Fe XVII Line Fluxes, and a Revised Iron Abundance,
Abstract
Lines of Fe XVII are prominent in the coronal spectrum below 25 A. The intensities of the lines of the 2p-3d transitions near 15 A have been used in conjunction with coronal models, and the assumption that the excited states are populated only by collisional excitation from the ground state ('coronal excitation'), to determine the Fe abundance. Eight lines of Fe XVII were observed which originated from the (2p)5(3s), (2p)5(3d) and (2s)(2p)6(3d) configurations in the coronal spectrum between 13 and 18 A. Using a more complete theoretical model, and higher resolution observations which allow a number of line blends to be resolved, the authors have revised earlier calculation of the coronal abundance of Fe, and find an iron abundance relative to hydrogen of .000026, which is in excellent agreement with the photospheric iron abundance. (Modified author abstract)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1974
- Accession Number
- AD0787204
Entities
People
- Arthur B. Walker Jr.
- Hugo R. Rugge
- Kay Weiss
Organizations
- The Aerospace Corporation