Analysis of the Solar Spectrum in the Spectral Range 33-110 Å
Abstract
Approximately 24 ions are identified in the soft X-ray spectrum of the Sun, including Fe VIII, IX, x, xi, xv, xvi, and Ni x and xi. Further identifications of 3p-4s transitions in Fe xii, xiii, and xiv are suggested. Identified as well as unidentified spectral features which enhance with solar activity are pointed out. The lines of the lithium-like ions excited by monopole and quadrupole collisions are very strong. Other examples of multipole excitation are pointed out in the spectra of Mg ix, Si xi, and Fe xvi. Element abundances relative to silicon are derived by the method of Pottasch. For plausible values of the Gaunt factor, the iron-to-silicon ratio is between one and two. The iron and silicon emission maximizes in stages Fe xi and Si x, respectively, indicating a general coronal temperature of 1.7 X 106 ° K. Quantitative agreement with the previous analyses of the Lin = 0 transitions (150-300 A) of the iron and silicon ions by Jordan (1966) and Pottasch (1967) is found
- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 1968
- DOI:
- 10.1086/149571
- Bibcode:
- 1968ApJ...152..545W