The addition of an external starshade to the Nancy Grace Roman Space Telescope will enable the direct imaging of Earth-radius planets orbiting at ∼1 AU. Classification of any detected planets as Earth-like requires both spectroscopy to characterize their atmospheres and multi-epoch imaging to trace their orbits. We consider here the ability of the Starshade Rendezvous Probe to constrain the orbits of directly imaged Earth-like planets. The target list for this proposed mission consists of the 16 nearby stars best suited for direct imaging, around which ∼10 to 15 planets are expected to be discovered. Of these planets, ∼1 to 2 will be Earth-like in mass and temperature. The field of regard for the starshade mission is constrained by solar exclusion angles, resulting in four observing windows during a two-year mission. We find that for Earth-like planets that are detected at least three times during the four viewing opportunities, their semi-major axes are measured with a median precision of 7 mas, or a median fractional precision of 3%. Habitable-zone planets can be correctly identified as such 96.7% of the time, with a false positive rate of 2.8%. If a more conservative criteria are used for habitable-zone classification (95% probability), the false positive rate drops close to zero, but with only 81% of the truly Earth-like planets correctly classified as residing in the habitable zone.

中文翻译：

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Starshade Rendezvous：来自多纪元直接成像的系外行星轨道约束

向南希格雷斯罗马太空望远镜添加外部遮光罩将能够直接成像以地球半径为轨道运行在 1 天文单位附近的行星。将任何检测到的行星分类为类地行星，需要光谱学来表征它们的大气层，并需要多纪元成像来追踪它们的轨道。我们在此考虑星影交会探测器限制直接成像的类地行星轨道的能力。这项拟议任务的目标列表包括最适合直接成像的 16 颗附近恒星，预计将在这些恒星周围发现 10 到 15 颗行星。在这些行星中，约 1 到 2 颗在质量和温度上与地球相似。遮光罩任务的关注领域受到太阳排斥角的限制，导致在为期两年的任务期间有四个观测窗口。我们发现，对于在四个观测机会中至少被探测到 3 次的类地行星，它们的半长轴测量的中位数精度为 7 mas，或中位数精度为 3%。宜居带行星的正确识别率为 96.7%，误报率为 2.8%。如果将更保守的标准用于宜居带分类（概率为 95%），误报率会下降到接近于零，但只有 81% 的真正类地行星被正确归类为居住在宜居带。误报率为 2.8%。如果将更保守的标准用于宜居带分类（概率为 95%），误报率会下降到接近于零，但只有 81% 的真正类地行星被正确归类为居住在宜居带。误报率为 2.8%。如果将更保守的标准用于宜居带分类（概率为 95%），误报率会下降到接近于零，但只有 81% 的真正类地行星被正确归类为居住在宜居带。