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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（STScI）所长已决定在观测周期27-29中，投入至多1000个轨道的所长自主支配时间，用于一项聚焦恒星形成及相关恒星物理研究的新哈勃紫外遗产项目。该项目名为ULLYSES（年轻恒星紫外遗产标准库，UV Legacy Library of Young Stars as Essential Standards），将提供年轻（<10 Myr）高、低质量恒星的紫外光谱参考样本。项目将观测麦哲伦云及本星系群中低金属丰度星系内的约150颗OB星，以及银河系内的约40颗T Tauri星（T Tauri stars）和褐矮星。此外，ULLYSES将对4颗典型T Tauri星进行监测，覆盖其不同自转相位，持续至少三个自转周期，时间跨度达数月至数年。由此构建的库将提供金属丰度远低于已充分研究样本的大质量恒星模板光谱；而低质量恒星样本将覆盖广泛的年龄、吸积率及质量范围，包括质量远低于0.5 M☉的天体。科学界获取的互补数据集将进一步丰富这一关于恒星演化最初10 Myr的大型紫外数据集的遗产价值。除聚焦高低质量恒星天体物理的核心目标外，该数据集还将推动星际介质（ISM）、星系际介质（CGM）、喷流及系外行星等领域的前沿研究。ULLYSES将效仿前沿场项目（Frontier Fields program）：所有获取的数据均为非专有数据。STScI的实施团队正开发高级科学数据产品、精密数据库及网站，以发布ULLYSES项目数据及来自空基与地基设施的ULLYSES目标样本辅助数据集。