Spectral and Photometric Measurements of Solar X-Ray Emission Below 60 Å

Abstract

On July 25, 1963, spectral measurements of solar X-ray emission were made with a Bragg X-Ray Crystal Spectrometer carried in an Aerobee Rocket. Line emissions from 0 VII, 0 VIII, N vii, and Fe XVII were recorded between 13 and 25 A. The 0 vii line emission came mainly from the solar disk as a whole; the Fe xvii emissions came from a localized active region near the center of the Sun. Studies of the distribution and sizes of X-ray emitting areas on the solar disk have been carried out using slit scans of the Sun. Sources of 8-is-A X-rays are geometrically smaller than 44-60-A sources. Some 8-is-A sources have dimensions of the order of 1'. On April 4,1963, essentially all the radiation observed in the 8-15-A band originated in active regions; about half the 6o-A emission was localized in the same regions, the remainder being distributed over the disk.