用于系外行星日冕仪观测的空间望远镜分镜级热灵敏度分析
Segment-level thermal sensitivity analysis for exo-Earth coronagraphy with segmented space telescopes
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中文总结 AI 辅助
该研究针对空间分镜式望远镜，建立分镜级热稳定性误差预算，通过分析温度梯度与波前变化的关联，优化热公差分配，明确分镜尺寸、公差与波前传感时间的权衡，为类地行星日冕仪观测提供支撑。
中文摘要 AI 辅助
类地行星的直接成像与表征需要超稳定波前，以在宿主恒星的日冕仪暗区实现100万亿分之一（ppt）的星光抑制水平。望远镜中的热漂移可能影响波前稳定性。在此背景下，我们提出了对类地行星探测至关重要的空间望远镜分镜级热稳定性误差预算，并明确了超稳定望远镜的要求。本研究采用多种分镜式主镜构型，每种构型均配备由空间望远镜科学研究所的分镜日冕仪设计与分析（SCDA）研究团队开发的对应切趾器方案，适配口径约6米的离轴空间望远镜设计。利用L3Harris技术公司提供的详细有限元模型，我们将主镜位置的温度梯度与每个分镜上的波前变化关联起来。我们分别采用基于成对分析模型的空间分镜望远镜成像灵敏度方法和批估计算法，为每个分镜分配静态和动态热公差。我们的分析表明，受切趾影响，主镜所有分镜的公差分配呈非均匀分布，且总体上，随着分镜数量增加，外侧分镜的公差要求放宽。我们观察到分镜尺寸、公差放宽与最优波前传感时间之间存在权衡，以实现期望的暗孔对比度。
英文摘要
Direct imaging and characterization of Earth-like planets require ultra-stable wavefronts to achieve a starlight suppression level of 100 parts per trillion (ppt) in the coronagraphic dark region of the host star. Thermal drifts in the telescope may affect the wavefront stability. In this context, we present a segment-level thermal stability error budget for segmented space telescopes crucial to Earth-like planet detection and specify requirements for an ultra-stable telescope. Our study utilizes multiple segmented primary mirror architectures, each with their respective apodizer solution developed by the Segmented Coronagraph Design & Analysis research team at the Space Telescope Science Institute, tailored to an off-axis ~6 m-aperture space telescope design. Using a detailed finite element model provided by L3Harris Technologies, we relate the temperature gradient at the location of the primary mirror to wavefront variations on each segment. We allocate both static and dynamic thermal tolerances for each segment using the Pair-based Analytical model for Segmented Telescope Imaging from Space sensitivity approach, and a batch-estimation algorithm respectively. Our analysis shows a non-uniform tolerance allocation across all segments of the primary mirror, as a result of apodization, and generally, with an increase in segment numbers, the tolerances for outer segments become less stringent. We observe trade-offs between segment size, tolerance relaxation and optimal wavefront sensing time to achieve a desired dark-hole contrast.
