Abstract
We observed two newly transits of the XO-1 planetary system. The observations of one of these transit events are done by using the 46-cm telescope hosted by Wise Observatory in Israel. The observations of the other one are done by using both 104-cm and 130-cm telescopes located at ARIES in India. We investigate the possibility for the transit timing variations (TTVs) in the orbital period of XO-1b that may aroused by the existents of an additional planet in this system, so we collected 28 transits from public data and analyzed with our own data. After the O-C diagram of the XO-1 system is obtained and analyzed, we found that a null TTV produces a fit with χred2=2.1764. We also find that the ephemeris with a sinusoidal function of a frequency 0.483985 has a fit with χred2=1.7962 and the one of a frequency 0.10706 has a fit with χred2=2.0867.