Abstract
THE ECLIPSING BINARY RX HERCULIS.—An extended series of observations of photographic magnitudes of this variable has lately been made and discussed by R. H. Baker and Edith E. Cummings (Laws Obs, Bull., No. 25). The observations were made by the extra-focal method and, in combination with the spectroscopic evidence, lead to the following conclusions:—The two stars are slightly ellipsoidal, and each has a radius about one and a half times that of the sun. The mass of each star is a little less than that of the sunt and the density is about one-fourth of the sun's density. The star eclipsed at principal conjunction is of magnitude 7–96, and is brighter by 0–12 i magnitude than its companion; its surface brightness, I mass, and density are greater than those of the fainter star by 12, 6, and 9 per cent, respectively, and it is of slightly earlier spectral class (A). The distance between the centres of the two stars is about five times the radius of either star, or about 5,280,000 km., At conjunction 70 per cent, of the disc of one star is eclipsed by the other. The period is 1.7785746 days (Shapley), and the semi-duration of eclipse 211. 53m. The photographic magnitude of the system is 7.264, and the magnitudes at primary and secondary minima 7.84 and 7.71 respectively. Outside eclipse the intensities generally increase towards secondary minimum, showing that the light of the star eclipsed at this time is augmented by radiation of its brighter companion.
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Our Astronomical Column . Nature 98, 216 (1916). https://doi.org/10.1038/098216a0
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DOI: https://doi.org/10.1038/098216a0