Title: The UV Legacy Library of Young Stars as Essential Standards (ULLYSES) Large Director's Discretionary Program with Hubble. I. Goals, Design, and Initial Results Show Chinese title

Title: 紫外辐射遗产年轻恒星作为基本标准（ULLYSES）大型主任任意计划与哈勃。 一． 目标、设计和初步结果

Abstract: Specifically selected to leverage the unique ultraviolet capabilities of the Hubble Space Telescope, the Hubble Ultraviolet Legacy Library of Young Stars as Essential Standards (ULLYSES) is a Director's Discretionary program of approximately 1000 orbits - the largest ever executed - that produced a UV spectroscopic library of O and B stars in nearby low metallicity galaxies and accreting low mass stars in the Milky Way. Observations from ULLYSES combined with archival spectra uniformly sample the fundamental astrophysical parameter space for each mass regime, including spectral type, luminosity class, and metallicity for massive stars, and the mass, age, and disk accretion rate for low-mass stars. The ULLYSES spectral library of massive stars will be critical to characterize how massive stars evolve at different metallicities; to advance our understanding of the production of ionizing photons, and thus of galaxy evolution and the re-ionization of the Universe; and to provide the templates necessary for the synthesis of integrated stellar populations. The massive star spectra are also transforming our understanding of the interstellar and circumgalactic media of low metallicity galaxies. On the low-mass end, UV spectra of T Tauri stars contain a plethora of diagnostics of accretion, winds, and the warm disk surface. These diagnostics are crucial for evaluating disk evolution and provide important input to assess atmospheric escape of planets and to interpret powerful probes of disk chemistry, as observed with ALMA and JWST. In this paper we motivate the design of the program, describe the observing strategy and target selection, and present initial results. Show Chinese abstract

Abstract: 专门选择以利用哈勃空间望远镜独特的紫外线能力，哈勃紫外遗产图书馆年轻恒星作为基本标准（ULLYSES）是一个大约1000个轨道的主任酌情项目——执行过的最大项目——产生了附近低金属含量星系中的O和B型恒星以及银河系中吸积的低质量恒星的紫外光谱库。ULLYSES的观测结果与档案光谱相结合，统一采样了每个质量范围的基本天体物理参数空间，包括大质量恒星的光谱类型、光度等级和金属量，以及低质量恒星的质量、年龄和盘吸积率。ULLYSES的大质量恒星光谱将对表征不同金属量下大质量恒星的演化至关重要；推动我们对电离光子产生的理解，从而了解星系演化和宇宙再电离；并提供合成综合恒星种群所需的模板。大质量恒星光谱也在改变我们对低金属含量星系的星际和环星系介质的理解。在低质量端，T Tauri恒星的紫外光谱包含大量关于吸积、风和温暖盘表面的诊断信息。这些诊断对于评估盘演化至关重要，并为评估行星大气逃逸和解释ALMA和JWST观测到的盘化学的强大探测提供了重要输入。在本文中，我们阐述了该计划的设计动机，描述了观测策略和目标选择，并展示了初步结果。