NEW SPECTROGRAPHIC OBSERVATIONS OF PECULIAR STARS

Abstract

NEW spectrographic observations of peculiar stars were discussed by O. Struve and P. Swings, of the McDonald and Yerkes Observatories, at the Autumn Meeting of the U.S. National Academy of Sciences held during October 13-15. The McDonald Observatory of the University of Texas (which is operated jointly by the University of Chicago and the University of Texas) is equipped with a powerful ultra-violet spectrograph. Two large crystal quartz prisms and lenses of quartz or of ultra-violet glass transmit stellar radiations to the limit imposed by the ozone bands in the atmosphere of the earth. During the past two and a half years this instrument has been used to record the spectra of a number of peculiar stars which had heretofore been investigated only in the ordinary photographic region of the spectrum. The ultra-violet region of the spectrum contains many important features: the limit of the Balmer series falls in the near ultra-violet where the lines crowd together and where photo-electric ionizations produce a marked discontinuity in the distribution of the continuous spectrum.