RUI: Blue Straggler Formation and Evolution in Globular Clusters

球状星团中蓝散星的形成和演化将通过流体动力学模拟来确定恒星合并的残余物。然后，这些残骸模型将被用于启动恒星演化计算。通过将理论演化轨迹与球状星团的动力学模型相结合，将有可能预测蓝散射粒子的可观测特征，包括它们的数量、亮度、颜色和在球状星团中的径向分布。这些流体动力学模拟将首次在单星-单星碰撞、单星-双星碰撞、双星-双星碰撞和双星碰撞中使用真实的主序母星模型。基于这些结果，将开发一套简单的算法，可以用于生成合并残留物的结构，而不需要实际运行大规模的流体动力学模拟。这些后续的恒星演化计算将是第一个处理旋转合并残留物的计算，也是第一个研究由于子午线环流导致的蓝色散布星中的化学混合的计算。我们将与观测结果进行详细的比较，比较的结果将对星团质量函数和二进制分数施加有趣的限制。通过这种方式，研究结果将使人们能够在球状星团的密集环境中探索恒星种群的性质。该项目由天文科学部资助。

AST-0071165LOMBARDIThe formation and evolution of blue straggler stars in glob-ular clusters will be modeled by using hydrodynamic simulations to determine the remnants of stellar mergers. These models of remnants will then be used to initiate stellar evolution calculations. By combining the theoretical evolutionary tracks with dynamical models of globular clusters, it will be possible to predict the observable characteristics of blue stragglers, including their numbers, luminosities, colors, and radial distribution in the globular cluster. These hydrodynamic simulations will be the first to use realistic models for the main sequence parent stars in single-single star collisions, single-binary collisions, binary-binary collisions, and binary coa-lescences. Based on these results, a set of simple algorithms will be developed that can be used to generate the structure of merger remnants without actually running large-scale hydrodynamic simulations. These subsequent stellar evolution cal-culations will be the first to treat rotating merger remnants and the first to examine chemical mixing in blue stragglers due to meridional circulation. Detailed comparisons with observations will be made and the results of the comparisons will place interesting limits on cluster mass functions and binary fractions. In this way, the results of the research will enable one to probe the nature of stellar populations in the dense environments of globular clusters.This project is funded by the Division of Astronomical Sciences.***