Star Cluster Evolution: Near and Far, Large and Small, Old and Young

星团演化：近与远、大与小、老与年轻

• 批准号: RGPIN-2019-06570
• 负责人: Sills, Alison
• 金额: $ 2.99万
• 依托单位: McMaster University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=763093
• 关键词: Star; Cluster; Evolution; Near; Far; Star; Cluster; Evolution; Near; Far

Star clusters are self-gravitating groups of stars with the same distance, age, and chemical composition. Stars are naturally formed in clustered environments, but only a few of those clusters will emerge as a self-contained, gravitatationally-bound entity from their natal molecular cloud. Nevertheless, the presence of close neighbours during the star formation process has important consequences for the masses and multiplicity of the stars that can form, and the survivability of planetary systems. Of those clusters that do emerge as clearly-identifiable objects, some will become massive old globular clusters. They have survived the entire galaxy formation process, including those times when two galaxies merged, or when a dwarf galaxy falls into its larger host galaxy. We can use the present-day properties of star clusters (size, mass, position, velocities, stellar content) to map galaxy structure and assembly over the last 10 billion years. But in order to use clusters to learn about star formation, planet formation or galaxy evolution, we need to understand how the clusters themselves form and change with time. The mature field of stellar dynamics (how stars move under their mutual gravity) provides many of the answers. However, stellar dynamics alone is not sufficient. It is important to also consider the interaction between the stars and star cluster with their external environment, such as the gas from which the stars formed, or the tidal field of the galaxy in which the cluster resides. The proposal describes a research program that will address these issues. In the next five years, we will concentrate on three specific projects: 1) to simultaneously and self-consistently model the formation and evolution of star clusters, their gas content, and their stellar populations, starting from the deeply embedded phase in molecular clouds, to produce the spherical, gas-free, open and globular clusters we see in the Milky Way today. 2) to trace the dynamical evolution of globular clusters and nuclear star clusters in their host galaxy, including episodes of galaxy mergers. In particular, we will quantify any observational signatures of accretion and merging on the individual clusters and the cluster populations as an ensemble. 3) to predict the expected observational signatures of the present-day massive old clusters as they are forming in the very early universe. Through simulations that combine stellar evolution, stellar dynamics, and hydrodynamics, we will produce a comprehensive picture of cluster formation and evolution on many scales of time, size, and distance.

恒星簇是具有相同距离，年龄和化学成分的恒星的自我磨损组。恒星自然形成在聚类的环境中，但只有少数簇会从其出生的分子云中出现作为一个独立的，引力结合的实体。然而，在恒星形成过程中，近邻的存在对可以形成的恒星的质量和多样性以及行星系统的生存能力产生了重要的影响。在那些确实可以识别为可见的物体的簇中，有些将变成巨大的旧球形簇。他们在整个星系形成过程中幸存下来，包括两个星系合并的时间，或者矮星系落入其较大的宿主星系时。在过去的100亿年中，我们可以使用恒星簇（大小，质量，位置，速度，恒星含量）的当前属性来绘制星系结构和组装。但是，为了使用簇来了解恒星形成，行星形成或星系进化，我们需要了解群集本身如何随着时间的推移形成和变化。恒星动力学的成熟领域（恒星如何在相互重力下移动）提供了许多答案。但是，仅凭恒星动力就不够。重要的是要考虑恒星与恒星簇与它们的外部环境之间的相互作用，例如恒星形成的气体，或簇属于恒星的潮汐场。该提案描述了将解决这些问题的研究计划。在接下来的五年中，我们将集中精力于三个特定项目：1）同时且一致地建模星形簇的形成和演变，它们的气体含量和它们的恒星种群，从分子云中的深层嵌入阶段开始，以产生球形，无气，开放式和球形群体，我们今天就会看到我们以MILKY的方式来看。 2）追踪其宿主星系中球状簇和核星簇的动态演化，包括星系合并的发作。特别是，我们将量化积聚的任何观察性签名，并在单个簇和集群种群上合并为合奏。 3）预测当今大型旧群集的预期观察性特征，因为它们在早期的宇宙中形成。通过结合了恒星进化，恒星动力学和流体动力学的模拟，我们将在许多时间，大小和距离的许多尺度上全面地描述群集形成和演变。