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.
The Kilodegree Extremely Little Telescope: Searching for Transiting Exoplanets in the Northern and Southern Sky
Kilodegree Extremely Little Telescope(KELT)是一个地面计划,旨在寻找围绕相对明亮恒星运行的系外行星。为了实现这一目标,KELT科学小组运营着两个行星设施-位于亚利桑那州维纳天文台的KELT-North和位于南非天文台的KELT-South。这些天文台使用的望远镜具有特别宽的视野,使KELT能够研究大量潜在的系外行星宿主恒星。瞄准明亮恒星的主要优势之一是,分布在世界各地的小型地面观测站可以很容易地跟踪检测到的系外行星候选者。本文将简要概述KELT-北和KELT-南调查,KELT后续合作进行的后续观测,以及迄今为止确认的系外行星发现,最后简要讨论KELT计划的未来。
A hybrid approach to generating diatomic line lists for high resolution studies of exoplanets and other hot astronomical objects: Updates to ExoMol MgO, TiO and VO line lists
Closeby Habitable Exoplanet Survey (CHES). IV. Synergy between astrometry and direct imaging missions of the Habitable World Observatory for detecting Earth-like planets
A Planetary Illusion's Funeral: Non-detection of a Gaia DR3 Exoplanet Candidate, and the Role of Intermediate-precision Radial Velocities in Gaia Exoplanet Follow-up
Centre for Astrophysics, University of Southern Queensland(南昆士兰大学天体物理中心);Max Planck Institute for Astronomy(马克斯·普朗克天文学研究所);Center for Astrophysics, Harvard & Smithsonian(哈佛-史密森尼天体物理中心)
虽然已经确认了数千颗系外行星,但关于个别发现的已知属性仍然很少,并且取决于探测技术。为了利用系外行星数据集的一小部分,需要开发工具来根据已知的测量结果估计缺失值。在这里,我们演示了神经网络的使用,该网络对具有六个属性的空间中的行星密度进行建模,然后用于估算缺失值的概率分布。我们的结果集中在行星的质量,无论是径向速度或过境技术的行星识别可以单独提供。神经网络可以在系外行星档案中的四个数量级上估算质量,并返回每个行星的质量分布,从而可以告知底层数据集的趋势。从径向速度探测得到的质量估计值的平均误差是观测值的1.5倍,而凌日观测值的平均误差是2.7倍。用这种方法得到的比邻星b的质量是$1.6^{\rm +0.46}_{\rm -0.36}$ M $_\oplus$,其中上界和下界是从对数质量概率分布的均方根偏差中得出的。该网络可以类似地估算其他潜在缺失的属性,我们用它来预测径向速度测量的行星半径,平均误差为观测值的1.4倍。神经网络在多维数据中搜索模式的能力意味着这种技术有可能大大扩展系外行星目录的使用。
Exoplanet population inference and the abundance of Earth analogs from noisy, incomplete catalogs
没有真正的太阳系外地球类似物是已知的。在类太阳恒星周围已经发现了数百颗行星,它们要么是地球大小但周期较短,要么是一年长的轨道,但稍大。在强有力的假设下,系外行星目录已经被用来对类太阳恒星拥有地球类似物的速率进行外推估计。这些研究是复杂的,因为每个目录都是由非平凡的选择效应和检测效率,以及每个属性(周期,半径等)审查。是用噪音来衡量的。在这里,我们提出了一个一般的层次概率框架,使合理的推断系外行星的人口,考虑到调查的完整性,并首次,观测的不确定性。我们能够比以前的研究对分布做出更少的假设;我们只要求发生率密度是周期和半径的平滑函数(采用高斯过程)。通过将我们的方法应用于合成目录,我们证明了它比基于逆检测效率加权的标准程序更准确地估计了整个人口。我们将该方法应用于G矮星周围的小行星候选者的现有目录(Petigura et al. 2013)。我们证实了以前的结果,半径分布改变斜率附近的地球半径。我们发现,地球类似物的率密度约为0.02(每星每自然对数箱的周期和半径),具有很大的不确定性。这一数字比以前用同样的数据但更强的假设所作的估计要小得多。
Ultra-Precise Astrometric Search for Exoplanets with SKA-VLBI
International Centre for Radio Astronomy Research (ICRAR), University of Western Australia(西澳大利亚大学国际射电天文研究中心);Joint Institute for VLBI ERIC (JIVE)(甚长基线干涉测量欧洲研究基础设施合作组织);Leiden Observatory, Leiden University(莱顿大学莱顿天文台)
Machine Learning for Exoplanet Detection in High-Contrast Spectroscopy: Revealing Exoplanets by Leveraging Hidden Molecular Signatures in Cross-Correlated Spectra with Convolutional Neural Networks
Institute for Particle Physics and Astrophysics, ETH Zürich(苏黎世联邦理工学院粒子物理与天体物理研究所);Seminar für Statistik, ETH Zürich(苏黎世联邦理工学院统计研讨会);Department of Astronomy, University of Michigan(密歇根大学天文系);Département d’Astronomie, Université de Genève(日内瓦大学天文系);STAR Institute, University of Liège(列日大学STAR研究所)
本文提出 MLCCS,用感知机和一维卷积神经网络分析互相关光谱中的隐藏分子信号,在 SINFONI K 波段模拟数据上显著提升暗弱系外行星探测灵敏度。
A Scalable Path to Astrometric Exomoon Discoveries with the Nautilus Space Observatory
University of Arizona(亚利桑那大学);Seoul National University(首尔国立大学);Massachusetts Institute of Technology(麻省理工学院);University of Maryland, College Park(马里兰大学帕克分校);NASA Goddard Space Flight Center(美国宇航局戈达德太空飞行中心);Center for Research and Exploration in Space Science and Technology II (CRESST II)(空间科学与技术研究探索中心二期);NASA Ames Research Center(美国宇航局艾姆斯研究中心);Max Planck Institute for Solar System Research(马克斯·普朗克太阳系研究所);University of Graz(格拉茨大学);Space Telescope Science Institute(太空望远镜科学研究所)