Theoretical Studies in Star Formation

恒星形成的理论研究

• 批准号: 0908553
• 负责人: Christopher McKee
• 金额: $ 43.17万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-01 至 2013-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0908553&HistoricalAwards=false
• 关键词: Theoretical; Studies; Star; Formation

In this project, Dr. McKee will undertake a theoretical study of magnetic fields and their role in star formation. Magnetic fields extract angular momentum from the gas that forms a star, thereby determining whether a gas cloud forms a single star or a binary. The radiation emitted by stars as they form can suppress fragmentation, thereby enabling just one or two stars to form in a region that would have formed many in the absence of thermal feedback. For the first time, frequency-dependent radiative transfer will be used to study the effects of thermal feedback in the formation of low-mass stars. Previous theoretical research has shown that ionized regions associated with the first stars are of particular importance since they determine the masses of these stars. In addition, this project will explore the formation of stars in groups and clusters. Most stars form in clusters, and indeed it is likely that the Sun formed in a large cluster that contained high-mass stars as well as low-mass stars like the Sun. The formation of star clusters is affected by the powerful feedback mechanisms that accompany star formation, including protostellar outflows and, for massive stars, photoionization and radiation pressure. Both semi-analytic theory and simulation will be used to investigate the formation of clusters of high-mass stars. The results will be compared with observations of star clusters in the Galaxy and of super star clusters in other galaxies. Star formation on galactic scales is determined by the properties of the interstellar medium of the galaxy. Star formation is central to contemporary astrophysics. As the process by which gas is transformed into stars, it determines the structure and evolution of galaxies. By tapping the nuclear energy in the gas left over from the Big Bang, it determines the luminosity of galaxies and, quite possibly, leads to the reionization of the universe. Most of the elements, including those that make up the world around us, are formed in stars. Finally, the process of star formation is inextricably tied up with the formation and early evolution of planetary systems. A theory of star formation must address both the formation of individual stars and the formation of systems of stars, ranging from clusters to galaxies. This grant will fund the education of one or more graduate students who will contribute to education and add to the diversity of the scientific work force. Developments in computational methodology will be published for use by the community.

在这个项目中，麦基博士将对磁场及其在恒星形成中的作用进行理论研究。磁场从形成恒星的气体中提取角动量，从而确定气体云形成的是单星还是双星。恒星形成时发出的辐射可以抑制碎裂，从而使一个在没有热反馈的情况下本可以形成许多恒星的区域只形成一到两颗恒星。首次使用频率相关的辐射传输来研究热反馈在低质量恒星形成中的作用。先前的理论研究表明，与第一批恒星相关的电离区具有特别重要的意义，因为它们决定了这些恒星的质量。此外，该项目还将探索恒星群和星团的形成。大多数恒星都是以星团形式形成的，事实上，太阳很可能是在一个大星团中形成的，其中既有像太阳这样的高质量恒星，也有低质量恒星。星团的形成受到伴随恒星形成的强大反馈机制的影响，包括原恒星流出，以及对于大质量恒星，光电离和辐射压力。半解析理论和模拟将被用来研究大质量星团的形成。结果将与银河系中的星团和其他星系中的超星团的观测结果进行比较。恒星在银河系尺度上的形成是由银河系星际介质的性质决定的。恒星形成是当代天体物理学的核心。作为气体转化为恒星的过程，它决定了星系的结构和演化。通过利用大爆炸遗留下来的气体中的核能，它决定了星系的光度，并很可能导致宇宙的再电离。大多数元素，包括构成我们周围世界的元素，都是在恒星中形成的。最后，恒星的形成过程与行星系统的形成和早期演化密不可分。恒星形成理论必须同时涉及单个恒星的形成和从星团到星系的恒星系统的形成。这笔赠款将资助一名或多名研究生的教育，这些研究生将为教育做出贡献，并增加科学工作者的多样性。计算方法的发展将公布，供社区使用。