标题： 宜居带连续度量标准用于优先考虑宜居世界观测目标 显示英文标题

标题： Continuous Habitable Zone Metric for Prioritizing Habitable Worlds Observatory Targets

摘要： 未来的直接成像空间望远镜，例如美国宇航局的宜居世界观测台（HWO），将是首批能够探测和表征附近类似太阳的恒星宜居带（HZ）内的类地系外行星的望远镜。由于即使是单个系统或系外行星也需要大量时间和资源，因此在优先安排观测时应考虑一个系统可能承载可探测生命的概率。一种优先排序的方法是估计一颗系外行星在宜居带内连续停留足够长的时间，使生命得以出现并对大气产生可检测影响的概率。我们利用贝叶斯方法计算围绕某颗恒星的特定轨道半径目前处于持续20亿年（Gyr）宜居带（CHZ$_2$）内的可能性，这一时间大致相当于地球上的生命显著氧气化大气所需的时间。我们将此方法应用于NASA系外行星探索项目任务恒星列表（EMSL）中的164颗恒星，这些恒星代表了未来直接成像任务最易接近的类似太阳恒星及其宜居带。通过考虑HWO假设的内工作角之外所有轨道半径处的CHZ$_2$可能性，我们定义了一种根据CHZ$_2$的可及性和总体范围来优先选择目标的指标。 我们发现对于晚F型和早期G型矮星，CHZ$_2$度量值在$3-4$千兆年时达到峰值，但初步确定比$\sim {F3}$型更早或比$\sim 6600$千开尔文更热的恒星，在观测时不太可能拥有一个CHZ$_2$。 显示英文摘要

摘要： Future direct imaging space telescopes, such as NASA's Habitable Worlds Observatory (HWO), will be the first capable of both detecting and characterizing terrestrial exoplanets in the habitable zones (HZ) of nearby Sun-like stars. Since this will require a significant amount of time and resources for even a single system or exoplanet, the likelihood that a system will host detectable life should be considered when prioritizing observations. One method of prioritization is to estimate the likelihood that an exoplanet has remained continuously within the HZ long enough for life to emerge and make a detectable impact on the atmosphere. We utilize a Bayesian method to calculate the likelihood that a given orbital radius around a star is currently in the 2 Gyr continuous habitable zone (CHZ$_2$), the approximate time it took life on Earth to significantly oxygenate the atmosphere. We apply this method to the 164 stars in the NASA Exoplanet Exploration Program Mission Star List (EMSL) for HWO, representing a preliminary sample of Sun-like stars with HZs most accessible to a future direct imaging mission. By considering the CHZ$_2$ likelihood at all orbital radii outside a hypothetical inner working angle for HWO, we define a metric for prioritizing targets according to the accessibility and total extent of the CHZ$_2$. We find that the CHZ$_2$ metric peaks between $3-4$ Gyr for late-F and early-G dwarfs, but tentatively determine that stars earlier than $\sim {F3}$ or hotter than $\sim 6600$ K are unlikely to have a CHZ$_2$ at the time of observation.