Practical planet prospecting
Practical planet prospecting
复制标题
实用的行星勘探
DOI：
10.1111/j.1365-2966.2004.07657.x
复制
发表时间：
2004
影响因子：
4.8
通讯作者：
M. Irwin
中科院分区：
文献类型：
--
作者：
S. Aigrain;M. Irwin
一些专门通过凌日法寻找系外行星的太空任务，如COROT、爱丁顿和开普勒，计划在未来几年内发射。他们将需要解决与自动和有效地探测受各种噪声源（包括恒星变化）影响的光变曲线中的行星凌日有关的问题。为了使这些飞行任务的科学回报最大化，必须在其发射日期之前开发和测试适当的算法。
从一个通用的最大似然方法开始，我们讨论了各种期间和过境发现方法之间的联系。这种层次结构的方法的自然端点被证明是一个快速，鲁棒性和统计上有效的最小二乘算法的基础上盒形过境。
这种方法是基于隐藏在随机噪声中的周期性过境的假设，通常假设叠加在具有规则连续采样的平坦连续体上。接下来，我们将展示如何将凌日发现方法推广到更现实的场景中，其中复杂的恒星（微）变化，不规则的采样和数据中的长间隔都存在。
模拟爱丁顿光变曲线，包括现实的恒星微变，不规则的采样和数据记录的差距，这种方法的测试，用于量化的性能。从视觉上看，这些系统效应可以完全压倒潜在的感兴趣信号。然而，在凌日持续时间短的情况下相比，占主导地位的时间尺度恒星的变化和数据记录段，它是可能的，从其余的解耦的凌日信号。
我们的结论是，即使有现实的污染恒星的变化，不规则的采样，并在数据记录的差距，它仍然是可能的，以接近理想化的理论界的效率检测凌日行星。特别是，空间飞行任务有可能接近探测G2V型恒星周围类地行星的范围。
A number of space missions dedicated to the search for exoplanets via the transit method, such as COROT, Eddington and Kepler, are planned for launch over the next few years. They will need to address problems associated with the automated and efficient detection of planetary transits in light curves affected by a variety of noise sources, including stellar variability. To maximize the scientific return of these missions, it is important to develop and test appropriate algorithms in advance of their launch dates.
Starting from a general-purpose maximum-likelihood approach we discuss the links between a variety of period- and transit-finding methods. The natural endpoint of this hierarchy of methods is shown to be a fast, robust and statistically efficient least-squares algorithm based on box-shaped transits.
This approach is predicated on the assumption of periodic transits hidden in random noise, usually assumed to be superposed on a flat continuum with regular continuous sampling. We next show how to generalize the transit-finding method to the more realistic scenario where complex stellar (micro) variability, irregular sampling and long gaps in the data are all present.
Tests of this methodology on simulated Eddington light curves, including realistic stellar microvariability, irregular sampling and gaps in the data record, are used to quantify the performance. Visually, these systematic effects can completely overwhelm the underlying signal of interest. However, in the case where transit durations are short compared to the dominant time-scales for stellar variability and data record segments, it is possible to decouple the transit signal from the remainder.
We conclude that even with realistic contamination from stellar variability, irregular sampling, and gaps in the data record, it is still possible to detect transiting planets with an efficiency close to the idealized theoretical bound. In particular, space missions have the potential to approach the regime of detecting Earth-like planets around G2V-type stars.