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


SOYDUGAN F. , SOYDUGAN F. , İbanoğlu C., Demircan O.

ASTRONOMISCHE NACHRICHTEN, cilt.327, ss.705-709, 2006 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 327 Konu: 7
  • Basım Tarihi: 2006
  • Doi Numarası: 10.1002/asna.200510620
  • Dergi Adı: ASTRONOMISCHE NACHRICHTEN
  • Sayfa Sayıları: ss.705-709

Özet

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 O-C 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 O-C 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 dP/dt = 7.1 s per century. The corresponding conservative mass transfer from less massive component to the more massive one is about 3.26 x 10(-7) M-circle dot yr(-1). It is interesting to see that the O-C 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 third-body. The lower limits of the masses of the hypothetical unseen components for CC Her and XZ Aql are found to be 2.69 M-circle dot and 0.47 M-circle dot, respectively. The third body of CC Her should be detectable not only spectroscopically but also photoelectrically, if it exists. (c) 2006 WILEY-VCH Verlag GmbH& Co. KGaA, Weinheim.