A Holistic Study of the W UMa Binary EQ Tau

Abstract

We present a new BVR light curves of the system EQ Tau carried out in the period from March to April 2006 using a 50 cm F/8.4 Ritchey Chretien telescope of the Baja Astronomical Observatory (Hungary, and 512*512 Apogee AP-7 CCD camera). The observed light curves were analyzed using the 2009 version of the Wilson-Devinney code. The results show that the more massive component is hotter than the low massive one by 99 K. A long term orbital period study shows that the period increases by the rate 8.946*10^(-11) day/cycle. Evolutionary state of the system has been investigated and showed that, the primary component of the system is located nearly on the ZAMS for both the M-L and M-R relations. The secondary component is close to the TAMS track for M-L and above the M-R relations.