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The Space Telescope Science Institute (STScI) Director has decided to devote up to 1000 orbits of Director.s Discretionary time in observing Cycles 27-29 to a new Hubble Ultraviolet Legacy program focused on star formation and associated stellar physics. This new program comma ULLYSES (UV Legacy Library of Young Stars as Essential Standards) comma will provide a UV spectroscopic reference sample of young (< 10 Myr) high- and low-mass stars. It will target over virgul150 OB stars in the Magellanic Clouds and lower metallicity galaxies in the Local Group comma and virgul40 T Tauri stars and brown dwarfs in the Milky Way. In addition comma ULLYSES will monitor 4 typical T Tauri stars over different rotational phases through at least three rotation periods comma and over timescales of months to years. The resulting library will provide template spectra of massive stars at metallicities substantially below the well studied comma while the low mass sample will cover a wide range of ages comma accretion rates comma and masses comma including objects down to well below 0.5 M_sun. The legacy of this large UV dataset on the first 10 Myr of stellar evolution will be enhanced by complementary datasets obtained by the scientific community. In addition to the core goals of the program related to stellar astrophysics of low and high mass stars comma this data will also enable exciting science in the fields of ISM comma CGM comma jets comma and exoplanets. ULLYSES will be modeled after the Frontier Fields programdoublePoint all data obtained will be non-proprietary. The implementation team at STScI is developing high-level science data products and a sophisticated database and website for disseminating data from the ULLYSES program and ancillary datasets for the ULLYSES target sample from space and ground-based facilities.

太空望远镜科学研究所（Space Telescope Science Institute，STScI）主任已决定，将第27至29号哈勃观测周期中总计最多1000个轨道的主任酌情观测时间（Director’s Discretionary Time），投入到一项全新的哈勃紫外遗产计划中，该计划聚焦恒星形成及相关恒星物理研究。这项全新计划名为ULLYSES（全称：“紫外遗产年轻恒星核心标准库”，UV Legacy Library of Young Stars as Essential Standards），将为年龄小于10 Myr（百万年）的高、低质量恒星提供紫外光谱参考样本。该计划将观测麦哲伦星系中的约150颗OB型恒星，以及本星系群内金属丰度较低的星系，同时还将观测银河系内的约40颗金牛座T型星（T Tauri stars）与褐矮星（brown dwarfs）。此外，ULLYSES还将对4颗典型金牛座T型星开展监测：覆盖其至少3个完整自转周期的不同自转阶段，监测时长跨度为数月至数年。该计划产出的光谱库，将提供金属丰度远低于现有研究常见水平的大质量恒星模板光谱；而低质量恒星样本则将覆盖宽泛的年龄、吸积率与质量范围，包含质量远低于0.5倍太阳质量（M☉）的天体。科学界后续获取的补充数据集，将进一步强化这套针对恒星演化最初1000万年的大型紫外数据集的科学遗产价值。除了围绕高低质量恒星恒星天体物理学的核心研究目标外，该数据集还将为星际介质（Interstellar Medium，ISM）、星系周介质（Circumgalactic Medium，CGM）、天体喷流以及系外行星（exoplanets）等领域的前沿研究提供支撑。ULLYSES计划将借鉴前沿领域计划（Frontier Fields program）的实施模式，所有获取的观测数据均无专属使用权，面向全球开放。STScI的实施团队正在开发高级科学数据产品、一套功能完善的数据库与官方网站，用于发布ULLYSES计划的相关数据，以及来自空间与地面观测设施的ULLYSES目标样本配套数据集。