16810

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）主任已批准，将27至29号哈勃观测周期中总计最多1000个轨道的主任酌情分配观测时间，用于一项全新的哈勃紫外遗产项目，该项目聚焦恒星形成及相关恒星物理研究。该项目命名为紫外年轻恒星核心标准遗产库（UV Legacy Library of Young Stars as Essential Standards, ULLYSES），将构建年龄小于10百万年（Myr）的大质量与小质量恒星的紫外光谱参考样本。项目将观测麦哲伦云与本星系群内低金属丰度星系中的约150颗OB星，同时观测银河系内的约40颗金牛座T型星与褐矮星。此外，ULLYSES将对4颗典型的金牛座T型星开展长期监测，覆盖其全部自转相位，观测时长至少涵盖3个完整自转周期，时间跨度为数月至数年。该光谱库将提供金属丰度远低于已被充分研究的大质量恒星的模板光谱；而小质量恒星样本则将涵盖宽泛的年龄、吸积率与质量区间，包括质量远低于0.5倍太阳质量（M☉）的天体。这套针对恒星演化最初10百万年的大型紫外数据集，其科学遗产价值将通过科学界获取的配套观测数据得到进一步扩充与提升。除了围绕大质量与小质量恒星的恒星天体物理学核心研究目标外，该数据集还将支撑星际介质（Interstellar Medium, ISM）、星系周介质（Circumgalactic Medium, CGM）、天体喷流以及系外行星等领域的前沿研究。ULLYSES项目将仿照哈勃前沿领域（Frontier Fields）项目开展，所有获取的观测数据均为非专有公开数据。STScI的项目实施团队正在开发高级科学数据产品，以及一套功能完善的数据库与专属数据发布网站，用于公开ULLYSES项目的全部观测数据，以及来自空间与地面观测设施的ULLYSES目标样本配套数据集。