Stellar spectral types were initially arranged alphabetically; however, subsequent detailed observations led to the consolidation and reordering of categories, establishing the current OBAFGKM ...

The principles involved in setting up any viable system of spectral classification are discussed. Their application is illustrated by reviewing the essential features of the original MK system of two ...

At the dawn of the universe, there was only hydrogen and helium. These elements made up all the galaxies and all the stars. But stars fuse hydrogen and helium into heavier elements, and large stars ...

EXPERIMENTS relating to the spectral fine structure of decametric radiation from Jupiter have been described 1,2. During the opposition of the planet in 1965 the high-resolution spectral experiment ...