X-rays from early-type stars are emitted by the corona or the stellar wind. The materials in the surface layer of early-type stars are not contaminated by nuclear reactions in the stellar inside. Therefore, abundance study of the early-type stars provides us an information of the abundances of the original gas. However, the X-ray observations indicate low-metallicity, which is about 0.3 times of cosmic abundances. This fact raises the problem on the cosmic abundances.
Experimental study of nuclear models. I. Decay schemes and nuclear reactions. II. Muonic x-ray studies. Progress report, October 1, 1975--August 31, 1976