Abstract
PHOTOMETRIC METHODS APPLIED TO VARIABLE STARS.—Dr. W. J. S. Lockyer, Director of the Norman Lockyer Observatory, Sidmouth, has recently contributed a very interesting study of the interesting star ø Persei (“The Spectrum of ø Persei, Type BoPe,” Monthly Notices, R.A.S., 85, 580, May 1925). The principal feature of the spectrum is the composite nature of the hydrogen lines and of the ionised lines of several metals, of which iron is the most prominent. For example, Hβ consists of a broad absorption band on which is superposed a bright emission band of lesser width, on which, again, is superposed a sharp absorption line. The ionised metallic lines, however, do not show the broad absorption band associated with the hydrogen lines. From observations, made more than twenty years ago, on the cyclical positional changes of the absorption lines, the star was recognised as a spectroscopic binary with a period of 126½ days. Lockyer's recent observations refer more particularly to the components of the bright emission bands—of Hβ, for example. The relative intensities of the two com ponents were measured by the wedge method, employed in the determination of spectroscopic parallaxes. In this way, cyclical changes were de tected, and the resultant period found by Lockyer agrees precisely with the period derived from various line-of-sight investigations.
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Our Astronomical Column. Nature 116, 256 (1925). https://doi.org/10.1038/116256a0
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DOI: https://doi.org/10.1038/116256a0