Abstract
SPECTROSCOPIC DETERMINATION OF STELLAR PARALLAX.—Since this method of parallax determination was devised the number of stars of which the parallax has been measured trigonometrically has increased considerably. With the view of testing the accuracy of the curves used for deducing absolute magnitude from the relative strength of certain spectral lines, Messrs. W. S. Adams and G. Strömberg have made an exhaustive comparison between their spectroscopic parallaxes, which now number some 1500, and the parallaxes deduced from direct measures and proper motions; the results are given in Proc. Nat. Acad. Sci., July, 1919. The stars are divided into five spec-teal groups, A7 to F8, F9 to G8, G9 to K3, K.4 to K9, and Ma to Md. The spectroscopic method has not yet been applied to types B6 to A6, as suitable spectral lines have not been found. The graphs show very satisfactory accordance, the weakest point being the fainter absolute magnitudes in the first group, where the spectroscopic determinations of distance are smaller than those measured directly. The last two groups indicate very clearly the division into giant and dwarf stars; this is also faintly indicated in the second and third groups, but not at all in the first.
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Our Astronomical Column . Nature 104, 511 (1920). https://doi.org/10.1038/104511a0
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DOI: https://doi.org/10.1038/104511a0