用相对天体测量法搜索宜居系外行星（SHERA）。I. 双星系统中的行星搜索案例
Searching for Habitable Exoplanets with Relative Astrometry (SHERA). I. The Case for Searching for Planets in Binary Star Systems
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中文总结 AI 辅助
SHERA任务采用衍射光瞳技术的小型空间望远镜，以微角秒级相对天体测量精度，搜索近邻多星系统类太阳恒星宜居带的岩质行星，研究双星形成对行星的影响，为未来类地行星探测任务做预研并探索行星三维轨道结构。
中文摘要 AI 辅助
发现类地行星（围绕类太阳恒星运行）是《2020年天文学十年调查》确定的优先科学目标，但这一目标受诸多因素阻碍，其中之一是近邻区域类太阳恒星的高多重性——近半数近邻类太阳恒星处于双星或更高阶恒星系统中，而目前绝大多数高效的系外行星探测技术难以探测这类系统中的小型行星。本文介绍SHERA（用相对天体测量法搜索宜居系外行星）NASA小型探测器任务概念：SHERA在一台小型、简易的光学空间望远镜上采用衍射光瞳技术，对7个近邻多星系统中的14颗类太阳恒星实现微角秒级精度的相对天体测量，结合光瞳与恒星双星特性在像平面提供精确参考。凭借该精度，SHERA可实现：（i）在最近的类太阳恒星宜居带中搜索岩质行星；（ii）研究双星形成对小型、宽分离行星的影响；（iii）为NASA未来多项用于表征类地行星的高优先级任务（如宜居世界天文台）开展关键的 precursor 观测。结合视向速度测量，SHERA相对天体测量还可探索双星系统中行星的三维轨道结构。
英文摘要
Discovering Earth-like planets orbiting Sun-like stars was identified as a priority science goal of the Astronomy 2020 Decadal Survey. It is confounded by many factors, one of which is the high multiplicity of Sun-like stars in the local neighborhood - half of nearby Sun-like stars are in binary or higher-order stellar systems, which are less amenable to the detection of small planets with almost all of the currently productive exoplanet detection techniques. Here we describe the SHERA (Searching for Habitable Exoplanets with Relative Astrometry) NASA Small Explorer mission concept. SHERA utilizes diffractive-pupil technology on a small, simple optical space telescope to achieve microarcsecond precision relative astrometry on 14 Sun-like stars in seven nearby multi-star systems, combining the pupil and stellar binarity to provide a precise reference in the image plane. With this precision, SHERA would enable: (i) a search for rocky planets in the habitable zones of the closest Sun-like stars; (ii) an investigation of the impact of binary star formation on small, widely separated planets; and (iii) the performance of crucial precursor observations on a number of high-priority targets of NASA's future missions to characterize Earth-like planets, such as the Habitable Worlds Observatory. When combined with radial velocity measurements, SHERA relative astrometry will also enable exploration of the three-dimensional orbital structure of planets in binary systems.
