Dynamics of Multiple Stellar Populations in Globular Clusters

球状星团包含数十万颗恒星，这些恒星被限制在半径只有几十光年的区域，比我们太阳周围的区域要密集得多。这些星系团是宇宙中最古老的天体之一，因此它们为我们银河系的形成提供了重要线索。新的观测表明，这些星系团中的恒星并不像之前认为的那样都是同时形成的，它们表现出一系列的化学成分。该小组将对球状星团的形成和演化进行基于计算机模拟的理论研究。参与这个项目的学生将学习有价值的计算和数据可视化技术，这些技术广泛适用于天文学以外的领域。许多观测研究现在已经提供了强有力的证据，表明大多数球状星团拥有多个具有不同化学性质的恒星群。这一发现代表着对球状星团的普遍看法的重大转变，即球状星团是由相同化学成分的恒星组成的系统。研究人员将对星系团的动力学历史进行建模，这样他们就可以追溯到恒星的形成过程中恒星的运动。他们将模拟这些球状星团中多个恒星群的形成和随时间的动态变化。该计划将进行广泛的模拟，以解决：1)多群体星系团的形成以及第一代和第二代恒星的初始结构和运动学性质的表征，2)第一代和第二代恒星动力学性质的早期和长期演化，3)宿主星系的内部动力过程和外部潮汐场在多群体星团演化中的作用，4)星系团恒星内容的基本属性的演变，以及它们如何受到多个人口的不同初始结构属性的影响。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Globular clusters contain hundreds of thousands of stars confined in a region with a radius of only a few tens of light-years, much more densely packed than the region around our Sun. These clusters are among the oldest objects in the Universe, so they provide important clues to the formation of our Milky Way Galaxy. New observations have shown that stars within these clusters are not all formed at once, as previously thought, and they exhibit a range of chemical compositions. This group will conduct a theoretical study based on computer simulations of the formation and evolution of globular clusters. Students involved in this program will learn valuable computational and data visualization techniques that are broadly applicable beyond astronomy.Many observational studies have now provided strong evidence that most globular clusters host multiple stellar populations characterized by different chemical properties. This discovery represents a major shift in the common view of globular clusters as systems composed of stars with the same chemical composition. The investigators will model the cluster’s dynamical history, so they can trace motions of the stars back to the formation of the stars. They will model of the formation and dynamical changes with time of multiple populations of stars in these globular clusters. This program will carry out extensive simulations to address: 1) the formation of multiple-population clusters and the characterization of the initial structural and kinematical properties of first- and second-generation stars, 2) the early and long-term evolution of the dynamical properties of first- and second-generation stars, 3) the role of internal dynamical processes and the external tidal field of the host galaxy in the evolution of multiple-population clusters, 4) the evolution of the fundamental properties of the cluster's stellar content and how they are affected by the different initial structural properties of multiple populations.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.