Abstract
A Paper ts of a Binary Star L. Baglow (Mon. Not. Roy. Ast. Soc., 108 No. 4; 1948) on "The Photometric US Sagittarii"is based on R. O. observations of the star, a description of as already been published (Mon. Not. Roy. Ast. Soc., 105, 212; 1945). Redman's measurements made photographically by the Fabry method and refer to an effective wave-length of 4400 A. ; these are shown in two figures together with a theoretical curve for both minima, computed by Baglow. Tables were calculated for various degrees of darkening, utilizing those given by Russell and Shapley, and elements were finally computed for an assumed coefficient of limb-darkening u equal to 0·4. The spectral type of the brighter star is given as B5, but that of the fainter one has not yet been observed. For the purpose of calculating the correction for reflexion it was assumed to be of type AO ; but until its spectrum has been observed the absolute dimensions of the system cannot be accurately determined, nor can the observed ellipticity of the components be compared with theoretical expectations. Table 3 of the paper shows the dimensions of the system for three different assumptions of the mass ratio, 1·0, 0·5 and 0·2, leading to the radii of the relative orbits as 4·7, 7·0 and 14 million km., respectively. It is believed that RS Sagittarii is a normal eclipsing binary with a circular orbit, the secondary star being considerably less massive than the primary but comparable in size with it. Suitable spectroscopic observations of the system could greatly reduce the large uncertainties in the photometric results.
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Photometric Elements of a Binary Star. Nature 163, 396 (1949). https://doi.org/10.1038/163396b0
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DOI: https://doi.org/10.1038/163396b0