Abstract
THE RADIAL VELOCITY OF β URSÆ MAJORIS.—From observations of the radial velocity made at Potsdam some years ago it was concluded by Ludendorff that β Ursse Majoris was a spectroscopic binary with a period of 27–16 days and total range of 15½ km./sec. Subsequent observations made at the Lick Observatory, however, gave a range of velocity no greater than that to be expected in the determinations for a constant-velocity star of type A. Further interest in the question was aroused last year by Guthnick and Prager's observations of the star with a photo-electric photometer, from which a variation through 0.02 mag. in a period of 0.3122 day was deduced; the Potsdam radial velocity values were thought to be consistent with this period. A further investigation of the radial velocity, with special reference to short-period changes, has since been undertaken at Mt. Hamilton (Lick Observatory Bulletin No. 284). Thirty-six plates were taken on three nights during February, 1916, but, as in the case of the earlier photographs, these do not appear to indicate a variation through any appreciable or dependable range of velocities. Prof. Campbell hopes that someone with less observing opportunity and more opportunity for computation will make a further effort to discover a periodicity of very small amplitude. The plates are available for loan to any experienced measurer of spectrograms who may have a plan for remeasuring them.
Article PDF
Rights and permissions
About this article
Cite this article
Our Astronomical Column . Nature 98, 196 (1916). https://doi.org/10.1038/098196a0
Issue Date:
DOI: https://doi.org/10.1038/098196a0