发表机构
University of California San Diego; Jet Propulsion Laboratory, California Institute of Technology; The Pennsylvania State University; Center for Exoplanets and Habitable Worlds, The Pennsylvania State University; Institute for Computational and Data Science, The Pennsylvania State University; Lunar & Planetary Laboratory, University of Arizona; University of Michigan; Space Telescope Science Institute; California Institute of Technology; Department of Astronomy, California Institute of Technology; University of California, Santa Cruz; University of California Observatories（加州大学圣地亚哥分校; 加州理工学院喷气推进实验室; 宾夕法尼亚州立大学; 宾夕法尼亚州立大学系外行星与宜居世界中心; 宾夕法尼亚州立大学计算与数据科学研究所; 亚利桑那大学月球与行星实验室; 密歇根大学; 太空望远镜科学研究所; 加州理工学院; 加州理工学院天文学系; 加州大学圣克鲁兹分校; 加州大学观测站）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
HWO可对邻近气态巨行星进行高信噪比测光和光谱观测，探测其大气成分、自转变化及系外卫星，并可能识别宜居卫星上的生物特征。
AI 中文摘要
凭借直接成像类地系外行星并搜寻其大气中生物特征的能力，即将到来的宜居世界观测台（HWO）还将收集邻近气态巨行星系外行星的高信噪比（S/N）反射光测光和光谱数据。此类高质量数据将允许对气态巨行星的大气成分、形成和运动学特性进行新颖的研究，并可能探测到这些行星周围的系外卫星。我们使用EXOSIMS直接成像任务模拟器，对ExEP目标列表中164颗恒星周围、处于类地和类木星辐照度下的木星半径气态巨行星的HWO观测进行建模。我们发现，HWO应能在5分钟积分时间内，对该辐照度范围内的气态巨行星实现S/N ≥ 5的宽带可见光探测。使用HWO进行10小时的R=1000近红外光谱观测，应能揭示类木星气态巨行星大气中的水、甲烷和氨吸收特征。对于ExEP恒星周围任何类地辐照度的气态巨行星，以及距离d≤7秒差距的类木星气态巨行星，HWO时间序列测光在一小时内应能超过1%的通量精度。在此节奏和精度下的时间序列光变曲线，在数十小时内可能揭示与木星相当的旋转诱导变率。对于位于ExEP恒星宜居带内、距离d≤10秒差距的木星大小行星，其高节奏光变曲线中可能探测到火星大小的系外卫星的凌食事件。对于太阳系距离d≤7秒差距内任何假设的、具有富氧大气的类地系外卫星，HWO或许能在深度（约400小时积分）R=1000光谱观测中，在母行星的光子噪声中探测到分子氧的光谱特征。此类卫星若存在，则代表了HWO可调查生物特征的其他宜居世界。
英文摘要
With the ability to directly image Earth-like exoplanets and search their atmospheres for biosignatures, the upcoming Habitable Worlds Observatory (HWO) will also collect high signal-to-noise ratio (S/N) reflected-light photometry and spectra of nearby gas giant exoplanets. Such high-quality data would allow novel investigations into gas giant atmospheric composition, formation, and kinematic properties, and could enable the detection of exomoons around these planets. We use the EXOSIMS direct imaging mission simulator to model HWO observations of Jupiter-radius gas giants at Earth-like and Jupiter-like instellations around the 164 stars in the ExEP target list. We find that HWO should be able to achieve S/N $\geq$ 5 broadband visible-light detections of gas giants in this instellation range within 5 minutes of integration. 10 hours of R=1000 near-IR spectroscopy with HWO should reveal water, methane, and ammonia absorption features in the atmospheres of Jupiter-like gas giants. HWO time-series photometry should exceed 1% flux precision in one hour for any Earth-instellation gas giants around ExEP stars, and for Jupiter-like gas giants at $d\leq$ 7 parsecs. Time-series light curves at this cadence and precision could, over tens of hours, reveal rotation-induced variability comparable to Jupiter's. Eclipses of Mars-sized exomoons may be detectable in high-cadence light curves of Jupiter sized planets in the habitable zones of ExEP stars at $d\leq$ 10 parsecs. For any hypothetical Earth-like exomoons with oxygen-rich atmospheres at $d\leq$ 7 parsecs from the Solar System, HWO might be able to detect the spectral signature of molecular oxygen amid the parent planet's photon noise in deep ($\sim$400 hour integration) spectroscopic HWO observations at R=1000. Such moons, if they exist, represent additional habitable worlds that HWO could investigate for biosignatures.
Comments80 pages, 12 figures, accepted to Journal of Astronomical Telescopes, Instruments, and Systems "Habitable Worlds Observatory Pre-Formulation Science, Architecture Concepts, and Technology Maturation"
