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Long-term orbital period behaviors of the neglected Algol type binaries: CC Herculis and XZ Aquilae

✍ Scribed by F. Soydugan; E. Soydugan; C. İbanoğlu; O. Demircan


Publisher
John Wiley and Sons
Year
2006
Tongue
English
Weight
183 KB
Volume
327
Category
Article
ISSN
0004-6337

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✦ Synopsis


Abstract

Orbital period variations of two neglected Algol type binaries, CC Her and XZ Aql, are studied based on all available times of minima. In the case of CC Her, it is found that the OC curve displays a tilted sinusoidal variation with an eccentricity of 0.54 ± 0.03 and a period of 52.4 ± 0.4 yr, which can be explained by the light‐time effect due to the presence of an unseen component. The course of the orbital period change in XZ Aql appears less reliable but its OC curve can be represented by a periodic variation with a period of 36.7 ± 0.6 yr superimposed on an upward parabola. The parabolic variation indicates a secular period increase with a rate of d__P__ /d__t__ = 7.1 s per century. The corresponding conservative mass transfer from less massive component to the more massive one is about 3.26 × 10^–7^ M~⊙~ yr^–1^. It is interesting to see that the OC variation of CC Her displays no evidence (as upward parabola) on the mass transfer characteristic for Algols. The periodic change of the orbital period of XZ Aql, like CC Her, may be caused by the presence of the thirdbody. The lower limits of the masses of the hypothetical unseen components for CC Her and XZ Aql are found to be 2.69 M~⊙~ and 0.47 M~⊙~, respectively. The third body of CC Her should be detectable not only spectroscopically but also photoelectrically, if it exists. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)