16108

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 virgul165 OB stars in the Magellanic Clouds and lower metallicity galaxies in the Local Group comma and virgul67 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.

空间望远镜科学研究所（Space Telescope Science Institute，STScI）主任已决定，在第27至29号观测周期内，将最多1000个观测轨道的主任自主酌情分配观测时间，投入一项全新的哈勃紫外遗产计划，该计划聚焦恒星形成及其相关恒星物理学研究。该新项目ULLYSES（UV Legacy Library of Young Stars as Essential Standards，即紫外年轻恒星基本标准遗产库）将构建年龄小于10百万年（Myr）的高、低质量年轻恒星的紫外光谱参考样本。其观测目标包括麦哲伦星云中的virgul165型OB星、本星系群内低金属丰度星系，以及银河系内的virgul67型金牛座T型星（T Tauri stars）与褐矮星。此外，ULLYSES将对4颗典型金牛座T型星开展监测：覆盖至少3个自转周期内的不同自转相位，监测时长跨度为数月至数年。该遗产库将提供金属丰度远低于现有成熟研究样本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倍太阳质量的天体。这项针对恒星演化最初10 Myr的大型紫外数据集，其科学价值将因科学界获取的补充数据集而进一步提升。除了围绕低质量与大质量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）、喷流以及系外行星等领域的前沿研究提供支撑。ULLYSES将仿照前沿领域计划（Frontier Fields program）实施，所有获取的数据均无专有版权，面向全球公开。STScI的实施团队目前正在开发高级科学数据产品，以及一套完善的数据库与官方网站，用于分发ULLYSES计划产生的数据，以及来自空间与地面观测设施的ULLYSES目标样本辅助数据集。