标题： 罗马日冕仪仪器对星际尘埃的灵敏度 显示英文标题

标题： Sensitivity of the Roman Coronagraph Instrument to Exozodiacal Dust

摘要： 围绕恒星系统适居带内和附近的彗星和小行星产生的温暖碎片，揭示了塑造行星系统的物理过程。 这种尘埃的散射光也是背景通量的来源，未来探测类地行星的任务必须克服这一背景通量。 本研究量化了南希·格蕾丝·罗曼空间望远镜日冕仪对来自外星黄道尘的散射光的敏感度。 使用一个由149颗邻近恒星组成的样本，这些恒星之前被选定为最佳探测适居系外行星的天体观测站，我们发现可观测到的具有可见\textit{内部}适居带边界的外星黄道尘盘的最大数量是六，可观测到的外侧适居带边界数量是74。 一个黄道尘被定义为太阳质量恒星周围22$m_{\rm V}\ $弧秒$^{-2}$的可见光表面亮度，近似于地球等效照射下的可见光散射光亮度。 在斑点限制的情况下，信号噪声比受限于斑点的时间稳定性而非散粒噪声时，日冕仪对适居带外星黄道尘的中位$5\sigma$敏感度为每分辨率元素12个黄道尘。 该估计是在日冕仪的内工作角处计算的，基于当前最佳性能估计，不考虑仪器性能不确定性的余量，并包括后处理斑点抑制因子。 对于以3$\times$太阳黄道尘为中位数的外星黄道尘水平的对数正态分布，我们发现罗曼日冕仪能够以95%置信区间跨越7-20个系统的概率，在13个系统中通过散射光检测到5$\sigma$次外星黄道尘盘。 这种灵敏度使罗曼日冕仪能够补充地面测量的外星黄道尘热辐射并限制尘埃反照率。 显示英文摘要

摘要： Exozodiacal dust, warm debris from comets and asteroids in and near the habitable zone of stellar systems, reveals the physical processes that shape planetary systems. Scattered light from this dust is also a source of background flux which must be overcome by future missions to image Earthlike planets. This study quantifies the sensitivity of the Nancy Grace Roman Space Telescope Coronagraph to light scattered by exozodi, the zodiacal dust around other stars. Using a sample of 149 nearby stars, previously selected for optimum detection of habitable exoplanets by space observatories, we find the maximum number of exozodiacal disks with observable \textit{inner} habitable zone boundaries is six and the number of observable outer habitable boundaries is 74. One zodi was defined as the visible-light surface brightness of 22 $m_{\rm V}\ $arcsec$^{-2}$ around a solar-mass star, approximating the scattered light brightness in visible light at the Earth-equivalent insolation. In the speckle limited case, where the signal-to-noise ratio is limited by speckle temporal stability rather than shot noise, the median $5\sigma$ sensitivity to habitable zone exozodi is 12 zodi per resolution element. This estimate is calculated at the inner-working angle of the coronagraph, for the current best estimate performance, neglecting margins on the uncertainty in instrument performance and including a post-processing speckle suppression factor. For an log-norm distribution of exozodi levels with a median exozodi of 3$\times$ the solar zodi, we find that the Roman Coronagraph would be able to make 5$\sigma$ detections of exozodiacal disks in scattered light from 13 systems with a 95\% confidence interval spanning 7-20 systems. This sensitivity allows Roman Coronagraph to complement ground-based measurements of exozodiacal thermal emission and constrain dust albedos.