VARIATION OF THE LIGHT AND PERIOD OF THE MAGNETIC CATACLYSMIC VARIABLE AM Her


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Kalomeni B. , Yakut K.

ASTRONOMICAL JOURNAL, cilt.136, ss.2367-2372, 2008 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 136 Konu: 6
  • Basım Tarihi: 2008
  • Doi Numarası: 10.1088/0004-6256/136/6/2367
  • Dergi Adı: ASTRONOMICAL JOURNAL
  • Sayfa Sayıları: ss.2367-2372

Özet

Ground-based, long-term optic variability of AM Her, covering the period between 2003-2008, has been conducted to study the features seen in both low and high states of the system. Low-state analysis shows the presence of short-term, low-amplitude light variations of about 0.02-0.03 mag with a mean power time between 16 s and 226 s. Brightness variations on the order of 0.7-2 mag, which could be due to the stellar activity of the component in the system, are also detected. A total of 30 years' times of minimum light given in the literature are combined with nine times of minima obtained in this study. We represented the (observed-calculated) diagram by a parabolic curve and also by two broken lines. Under the assumption of a parabolic variation, we estimate an increase in period, dP/dt = 7.5(1.2) x 10(-9) days yr(-1), with a mass transfer rate of. M = 8(2) x 10(-9) M(circle dot) yr(-1), in agreement with the previous findings by a different method.