Extrasolar planet detection by binary stellar eclipse timing: evidence for a third body around CM Draconis
H. J. Deeg, B. Ocaña, V. P. Kozhevnikov, D. Charbonneau, F. T. O'Donovan, L. R. Doyle
备注：
10 pages, 5 figures, accepted by A&A. V2: fixed spelling of one of the authors. V3: fixed error in distance to CM Dra, implying minor changes to several derived numbers
Context: New eclipse minimum timings of the M4.5/M4.5 binary CM Dra were obtained between the years 2000 and 2007. In combination with published timings going back to 1977, a clear non-linearity in observed-minus-calculated (O-C) times has become apparent. Several models are applied to explain the observed timing behavior.
Aims: Revealing the processes that cause the observed O-C behavior, and testing the evidence for a third body around the CM Dra system.
Methods: The O-C times of the system were fitted against several functions, representing different physical origins of the timing variations.
Results: An analysis using model-selection statistics gives about equal weight to a parabolic and to a sinusoidal fitting function. Attraction from a third body, either at large distance in a quasi-constant constellation across the years of observations or from a body on a shorter orbit generating periodicities in O-C times is the most likely source of the observed O-C times. The white dwarf GJ 630.1B, a proper motion companion of CM Dra, can however be rejected as the responsible third body. Also, no further evidence of the short-periodic planet candidate described by Deeg et al. (2000) is found, whereas other mechanisms, such as period changes from stellar winds or Applegate's mechanism can be rejected.
Conclusions: A third body, being either a few-Jupiter-mass object with a period of 18.5+-4.5 years or an object in the mass range of 1.5M_jup to 0.1M_sun with periods of hundreds to thousands of years is the most likely origin of the observed minimum timing behavior.
The orbital period of the eclipsing dwarf nova CG Draconis
我们对矮新星CG Dra进行了时间分辨测光，并首次确定它是一个食系统。通过测量日食的时间，我们确定轨道周期为0.18864（4）d，或4 h 31 m 38 +/- 3s。这个值与早期光谱研究中提出的两个周期中较短的一个一致。轨道周期将CG Dra置于周期间隙之上。对称食的持续时间短（半高宽18+/-2分钟，或轨道周期的0.066（7））且较浅（平均0.16+/-0.02等），这表明食是掠食，与轨道倾角刚好在临界值以上一致。闪烁持续整个日食，这意味着闪烁的来源没有被第二颗恒星掩盖。
Theory for the Secondary Eclipse Fluxes, Spectra, Atmospheres, and Light Curves of Transiting Extrasolar Giant Planets
我们已经创建了一个通用的方法来计算波长依赖的光变曲线的接近太阳系外的巨行星（EGPs），因为他们穿越自己的轨道。重点是过境EGPs HD 189733 b，TrES-1，和HD209458 b，我们计算行星/恒星流量比在二次日食，并比较它们与斯皮策数据点到目前为止，在中红外。我们介绍了一个简单的参数化的热量重新分配到行星的夜面，推导出这个参数（P_n）的约束，并提供了一个一般的一套预测行星/恒星的对比度作为波长，模型和相位的函数。此外，我们还计算了每个凌日行星/Pn对的昼侧和夜侧平均大气温度/压力廓线，利用现有的和预期的Spitzer数据可以探测严重辐照的EGP的大气热结构。我们发现，基线模型在拟合当前的二次日食数据集方面做得很好，但是斯皮策的误差条还不够小，无法清楚地区分所有各种可能性。
Observational Limits on Terrestrial-Sized Inner Planets Around the CM Draconis System Using the Photometric Transit Method with a Matched-Filter Algorithm
Towards a Small Prototype Planet Finding Interferometer: The next step in planet finding and characterization in the infrared
在过去的几年中，相当大的努力已经指向大规模（>> $1 Billion US) missions to detect and characterize earth-like planets around nearby stars, such as the Terrestrial Planet Finder Interferometer (TPF-I) and Darwin missions. However, technological and budgetary issues as well as shifting science priorities will likely prevent these missions from entering Phase A until the next decade. The secondary eclipse technique using the Spitzer Space Telescope has been used to directly measure the temperature and emission spectrum of extrasolar planets. However, only a small fraction of known extrasolar planets are in transiting o…
Efficient identification of exoplanetary transit candidates from SuperWASP light curves
凌日系外行星只占恒星系统范围的一小部分，这些恒星系统在使用小孔径相机阵列的宽视场调查中显示出周期性的浅暗。在这里，我们提出了一个有效的选择策略，后续观察，来自光变曲线的分析样本的67个SuperWASP目标，通过选择测试，我们在早期的论文中使用，但随后被确定为行星主机或天体物理误报。我们使用马尔可夫链蒙特卡罗分析的SuperWASP光变曲线确定系统参数。我们使用卡方约束优化结合贝叶斯先验的基础上，预计从2 MASS J-H颜色的主要序列的质量和半径。贝叶斯性质的分析，使我们能够量化离开主序星的质量半径关系和概率的伴侣半径小于1.5木星半径。当通过直接光变曲线分析来检测具有不相等的主日食和次日食的双星，以及具有由SuperWASP解决的孔径混合的物体时，我们发现原始67颗恒星中只有13颗，包括样本中的三颗已知行星，有资格进行后续研究。这表明，行星发现的“命中率”应该可以达到五分之一以上。此外，符合条件的恒星双星可能具有天体物理学上有趣的恒星或亚恒星双星。
