Journal of Astronomy and Space Sciences (Dec 2004)

Period Change of the Contact Binary AH Tauri

  • Dongjoo Lee,
  • Chung-Uk Lee,
  • Jae Woo Lee,
  • Seung-Lee Kim,
  • Kyu-Dong Oh,
  • Chun-Hwey Kim

DOI
https://doi.org/10.5140/JASS.2004.21.4.283
Journal volume & issue
Vol. 21, no. 4
pp. 283 – 294

Abstract

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New BVRI photometric observations of the contact binary AH Tau were performed with the 61 cm reflector and a 2K CCD camera at the Sobaeksan Optical Astronomy Observatory during seven nights from September to December, 2001. A total of 144 times of minima observed up to date, including three times of minima obtained from our observation, were analyzed. It is found that the orbital period of AH Tau has varied in a cyclic way superposed on a secular period decrease. The rate of the secular period decrease is calculated to be 1^s.04 per century, implying that a mass of about 3.8 × 10-8 M⊙/yr from the more massive primary flows into the secondary if a conservative mass transfer is assumed. Assuming that the sinusoidal period variation is produced by a light-time effect due to an unseen third body, the resultant semi-amplitude, period, and eccentricity for the deduced light-time orbit are obtained as 35.4 years, 0.014 day and 0.52, respectively. The mass of the third-body is calculated as about 0.24 M⊙ when the third body is assumed to be coplanar with AH Tau system.

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