arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0909.1564astro-ph.EP
收藏

系外行星TrES-1和TrES-2的Transit时序分析

Transit timing analysis of the exoplanets TrES-1 and TrES-2

M. Rabus, H. J. Deeg, R. Alonso, J. A. Belmonte, J. M. Almenara

摘要:

这项工作的目的是详细分析从TrES-1和TrES-2的过境光变曲线,在一个为期三至四年的时间内获得的,以寻找观测到的中期过境时间的变化,并设置额外的第三体的存在的限制。利用IAC 80厘米望远镜,我们在几年内观测了TrES-1和TrES-2的凌日。基于这些新数据和以前发表的工作,我们研究了观测到的光变曲线,并寻找观测到的和计算出的(基于固定星历)渡越时间之间的差异。为了模拟可能的凌日时间变化,我们使用了不同阶次的多项式,模拟了对应于扰动第三质量和正弦拟合的O-C图。对于每个模型,我们计算卡方残差和虚警概率(FAP)。对于TrES-1,我们可以根据我们从地面的凌日观测结果排除3:2和2:1 MMR中具有高FAP的行星同伴(>1 M_地球)。此外,由e引起的光时间效应的存在。G.在7.8天文单位的距离上可能存在一颗0.09 M太阳质量的恒星。至于TrES-2,我们发现了一个更好的星历Tc = 2,453,957.63512(28)+ 2.4706101(18)x Epoch和一个周期为0.2天的正弦函数的良好拟合,与TrES-2周围的月亮和57秒的振幅兼容,但它不是一个独特的低卡方值,将表明一个明确的信号。在这两种情况下,TrES-1和TrES-2,我们能够把额外的扰动质量的存在上限。我们还得出结论,任何可能表明系外卫星的正弦变化都需要通过进一步的观测来证实,并注意到TrES-2在开普勒太空望远镜的视野中。

英文摘要:

The aim of this work is a detailed analysis of transit light curves from TrES-1 and TrES-2, obtained over a period of three to four years, in order to search for variabilities in observed mid-transit times and to set limits for the presence of additional third bodies. Using the IAC 80cm telescope, we observed transits of TrES-1 and TrES-2 over several years. Based on these new data and previously published work, we studied the observed light curves and searched for variations in the difference between observed and calculated (based on a fixed ephemeris) transit times. To model possible transit timing variations, we used polynomials of different orders, simulated O-C diagrams corresponding to a perturbing third mass and sinusoidal fits. For each model we calculated the chi-squared residuals and the False Alarm Probability (FAP). For TrES-1 we can exclude planetary companions (>1 M_earth) in the 3:2 and 2:1 MMRs having high FAPs based on our transit observations from ground. Additionally, the presence of a light time effect caused by e. g. a 0.09 M_sun mass star at a distance of 7.8 AU is possible. As for TrES-2, we found a better ephemeris of Tc = 2,453,957.63512(28) + 2.4706101(18) x Epoch and a good fit for a sine function with a period of 0.2 days, compatible with a moon around TrES-2 and an amplitude of 57 s, but it was not a uniquely low chi-squared value that would indicate a clear signal. In both cases, TrES-1 and TrES-2, we were able to put upper limits on the presence of additional perturbers masses. We also conclude that any sinusoidal variations that might be indicative of exomoons need to be confirmed with higher statistical significance by further observations, noting that TrES-2 is in the field-of-view of the Kepler Space Telescope.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑