DISRUPTED ATOMS AS CONSTITUENTS OF THE STARS

Abstract

It has been recognized for the past fifty years that a chemical element may exist in more than one state in the atmosphere of a star, and the research centered about this fact has been one of the important aids which laboratory investigation has rendered to astronomy. Years before the electron was thought of, stars which were obviously of different types were found to give two entirely distinct spectra of an element. One of these spectra was observed in the laboratory when iron, for example, was vaporized in the electric arc. The other spectrum appeared when a high-voltage spark passed between the same iron electrodes. Lines of the first group usually remained visible in the spark, but the new lines were so much stronger that they have since been known as lines. In stellar spectra the strength of these enhanced lines gave at once a means of classifying the stars according to temperature, on the reasonable assumption that high temperature in a star can produce the same disturbance of the atom as high electrical discharges in the laboratory. The nature of this disturbance was made clear as the modern