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arXiv 1003.4700astro-ph.IMastro-ph.EP
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直接探测估计系外行星发现的新完备性方法

New Completeness Methods for Estimating Exoplanet Discoveries by Direct Detection

Robert A. Brown, Remi Soummer

摘要:

我们报告了新的方法来评估现实的观测计划,搜索恒星的行星直接成像,观测是从优化的恒星列表中选择的,恒星可以观察到多次。我们展示了这些方法如何为任务及其仪器的设计带来关键的见解。这些方法提供了对观测计划结果的估计:发现(探测和/或表征)的概率分布,以及对行星出现率(eta)的估计。我们表明,这些参数可以准确地估计从一个单一的任务模拟,而不需要一个完整的蒙特卡洛任务模拟,我们证明了这种新方法的准确性。我们的方法提供了为特定科学目标定义任务的工具,例如由预期的发现数量及其置信水平定义。我们详细介绍了如何建立一个优化的恒星列表以及如何选择连续的观测结果。我们的方法还提供了其他关键的任务属性,例如预期要搜索的恒星数量,以及零发现的概率。由于这些属性强烈依赖于任务规模,我们的方法是直接适用于设计这样的未来任务和提供指导的任务和仪器设计的基础上的科学性能。我们用实际计算和探索性设计参考任务来说明我们的新方法,JWST使用遥远的遮光板来减少焦平面上的散射和衍射星光。我们估计将发现5颗可居住的地球质量的行星,并用光谱学进行表征,0发现的概率为0.004,假设JWST观测时间的一小部分(7%),eta=0.3,以及70次观测访问,受恒星阴影燃料的限制。

英文摘要:

We report new methods for evaluating realistic observing programs that search stars for planets by direct imaging, where observations are selected from an optimized star list, and where stars can be observed multiple times. We show how these methods bring critical insight into the design of the mission & its instruments. These methods provide an estimate of the outcome of the observing program: the probability distribution of discoveries (detection and/or characterization), & an estimate of the occurrence rate of planets (eta). We show that these parameters can be accurately estimated from a single mission simulation, without the need for a complete Monte Carlo mission simulation, & we prove the accuracy of this new approach. Our methods provide the tools to define a mission for a particular science goal, for example defined by the expected number of discoveries and its confidence level. We detail how an optimized star list can be built & how successive observations can be selected. Our approach also provides other critical mission attributes, such as the number of stars expected to be searched, & the probability of zero discoveries. Because these attributes depend strongly on the mission scale, our methods are directly applicable to the design of such future missions & provide guidance to the mission & instrument design based on scientific performance. We illustrate our new methods with practical calculations & exploratory design reference missions for JWST operating with a distant starshade to reduce scattered and diffracted starlight on the focal plane. We estimate that 5 habitable Earth-mass planets would be discovered & characterized with spectroscopy, with a probability of 0 discoveries of 0.004, assuming a small fraction of JWST observing time (7%), eta=0.3, and 70 observing visits, limited by starshade fuel.

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。

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