MG IX Line Ratios in the Sun
Abstract
Attention is given to theoretical Mg IX electron density sensitive emission-line ratios derived using electron impact excitation rates interpolated from accurate R-matrix calculations, which are presented for R1 = I(443.97 A)/I(368.07 A), R2 = I(439.17 A)/I(368.07 A), R3 = I(368.07 A)/I(443.07 A), and R4 = I(441.20 A)/I(368.07 A). A comparison of these with observational data for solar flares on board Skylab reveals excellent agreement between theory and observation for R1 and R2, which confirms the usefulness of these ratios as Ne-diagnostics for solar flares, as well as providing experimental support for the accuracy of the atomic data adopted in the line ratio calculations. The observed values of both R3 and R4 generally imply unrealistically high electron densities, which is argued to be due to blending in the 443.40- and 441.20-A lines, probably with Ar IV 443.44 A and Mg VI/Mg VII 441.22 A, respectively.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 1992
- DOI:
- 10.1086/171024
- Bibcode:
- 1992ApJ...386..371K
- Keywords:
-
- Line Spectra;
- Magnesium;
- Metallicity;
- Solar Flares;
- Solar Spectra;
- Emission Spectra;
- Ultraviolet Astronomy;
- Solar Physics;
- ATOMIC DATA;
- ATOMIC PROCESSES;
- SUN: FLARES;
- ULTRAVIOLET: SOLAR SYSTEM