Discovery of a Near New Star

Abstract

DR. OTTO STRTUVE, Yerkes Observatory, reports the discovery of a new star to which the name Wolf 424 has been assigned. It is described as of the twelfth visual magnitude, and its spectrum is of the very late M-type. As is well known, it is possible to determine stellar distances to a fair degree of accuracy from their spectral type. The examination of the spectra of stars of known distances shows that the intensities of certain lines in their spectra vary with the true luminosity of the stars. Conversely, by studying lines in the spectra of stars, the real light output can be estimated, and this, combined with the star's apparent brightness, furnishes the necessary data for determining the distance. In the case of the new star, this method has been applied, and the spectroscopic parallax so found shows that it is probably closer to us than a Centauri. It should be pointed out, however, that there is considerable doubt about the true distance, for various reasons. Very great accuracy in determining the intensities of the lines is essential, and in addition, if, as is possible, the star is a very close unresolved binary, this would vitiate the results to some extent. There is no doubt about the star being fairly close to us, for which reason its trigonometrical parallax can be determined in about six months and its distance found by this independent method. Until this has been done, it is advisable to suspend judgment regarding Dr. Struve's conjecture that it may be the nearest star.