view Abstract Citations (38) References (14) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Coronal Line Intensities at the Khartoum Eclipse. Athay, R. G. ; Roberts, W. O. Abstract Coronal line and continuum intensities were measured at several position angles on the limb and as a function of height above the limb on the slitless spectrograms obtained at Khartoum by the High Altitude Observatory. The lines XX 5303, 6374, and 7892 and the continuum were measured at fifteen points around the limb. The relative line and continuum intensities around the limb showed large variations. In one active region where the emission in some lines was intense, the yellow coronal line X 5694 was observed. In this same region the lines X 6702 and X 7060 were intense enough to measure, and it was found that lines of high ionization potential were at maxima in intensities, whereas lines of low ionization potential were at minima. The yellow line was at maximum in this region, confirming that it is a high4oniza- tion-potentia] line. The correlation between line and continuum intensities was found to increase markedly as the ionization potential increased for the three lines studied. The correlation between line intensities was found to increase as the difference in ionization potential decreased. Intensities of X 5303, X 7892, and the continuum were measured as a function of height above the limb in four regions. Two of these regions were active centers, one of which showed the yellow line, and two were more nearly average regions. The change of X 7892 intensities with height in the latter two regions showed that the maximum intensity occurred below 10,000 km. Changes in the relative intensities of the two lines with height showed that in the yellow-line region the temperature decreased with height, but in the other regions the temperature increased with height. A comparison of the changes in line intensities to the changes in continuum intensities showed that the average temperature in the active regions was above the value at which the line X 5303 had a maximum intensity, but in the two more normal regions the temperature was between the limits where the lines X 5303 and X 7892 have maxima. The active regions were found to be regions of high density. Publication: The Astrophysical Journal Pub Date: January 1955 DOI: 10.1086/145980 Bibcode: 1955ApJ...121..231A full text sources ADS |