系外行星研究组知识库

利用云南天文台1 m望远镜以及丽江天文观测站2.4 m望远镜,分别在2009年和2012年对凌食太阳系外行星系统HAT-P-8进行了测光观测.为了提高凌食信号的信噪比,使用coarse de-correlation和SyeRem两种方法对测光数据中的系统误差进行了改正.应用MCMC(Markov Chain Monte Carlo)方法对3组数据进行同时分析求解获得了HAT-P-8系统新的物理参数.得到HAT-P-8b的半径为Rp=1.28 R_J(R_J为木星半径),这比该行星发现时Latham等人给出的数值要小,而与最近Mancini等人所得的结果一致.通过线性拟合23个慎重挑选的凌食中心时刻,得到HAT-P-8b新的轨道周期P=3.0763461±0.0000021 d,并且从(O-G)(观测值减计算值)分析中没有发现显著的TTV(Transit Timing Variation)信号.

Three transit events of HAT-P-8 are observed by using the 1 m telescope of Yunnan Observatory and 2.4 m telescope of Lijiang Observing Station in 2009 and 2012, respectively. The observational data were reduced with the coarse de-correlation and SysRem algorithms in order to obtain high signal to noise ratio for the transit feature. The MCMC (Markov Chain Monte Carlo) technique is applied to analyze three transit light curves simultaneously, then the new parameters of HAT-P-8 system are derived. The new value of the radius for HAT-P-8b is smaller than the one given by Latham et al., but it is consistent with the value derived by Mancini et al. recently. By linear fitting to the 23 mid-transit times with high precision, the orbital period of HAT-P-8b is refined as P=3.0763461±0.0000021 d. No obvious TTV (Transit Timing Variation) signal can be found from the present (O-C) analysis.