Metallic Lines in the Lower Chromosphere Observed at Peruvian Eclipse, II. Interpretation of Chromospheric Excitations by Multi-Level Line Transfer
Abstract
With a view to explaining the characteristics observed at the Peruvian eclipse, multi-level transfer problems were solved in cases of Fe I, Zr ii, and V ii with atomic models consisting of 7 to 10 levels and with radiative transitions from 5 to 9 levels. It was shown that for most lines, excitation temperatures at the optical depth of unity in the center of each line are represented by one curve which is very similar to the distribution of (1967). The excitation temperature departs upwards from GER's (1967) distribution at the depths ro <1, taking on a fish-bone appearance. In the cases of Zr ii and V ii, lines are found to be formed predominantly by the scattering of photospheric radiation. The excitation temperatures at such heights as can be observed in the eclipse turned out to agree well with those derived from flash analyses, and to be larger than the local electron temperature. In the case of Fe I, all lines are formed at the level of the temperature minimum or higher. Chromospheric excitations can be reproduced for weaker lines, but for stronger lines the temperature rise as observed in the flash could not be explained by such a uniform model as the Bilderberg Continuum Atmosphere. Key words: Eclipse; Multi4evel transfer; Metallic lines; Excitation temperature.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- 1971
- Bibcode:
- 1971PASJ...23..217T