Young Star Dynamical Mass Ratios Down to and Across the Substellar Boundary

要了解我们银河系的过去和未来的演化，就必须对恒星形成有一个大致的了解。恒星形成区域是否共享全球属性，例如分子云核中的初始角动量分布？年轻双星的频率、分布和性质提供了关键信息。这个项目通过研究附近恒星形成区域中最接近的年轻双星系统，进一步加深了我们对恒星形成的一般理解。这些系统，即光谱双星，特别有用，因为它们的径向速度变化可以非常精确地测量，因此它们的质量比和最终质量可以在没有假设的情况下准确地确定。使用高分辨率红外光谱进行这些测量，确保即使是光谱系统中最微弱和最小质量的次要物质也能被识别出来。拟议项目的重点是主序列中较低且不太为人所知的一端。低质量光谱双星的质量比分布将告诉我们不同恒星形成区恒星形成的全球特征。未来基于这些质量比的绝对质量的确定将对开发低质量和亚恒星物体的形成和演化的准确模型至关重要。广泛的影响：结果的广泛传播采取在被引用的期刊、新闻稿、海报和在全国会议上发表的演讲的形式，增加了研究人员、同事和研究生的科学和技术理解。公众可在网上查阅适用于各种天体物理数据的独特数据集和软件。

Having a broad picture of star formation is necessary for understanding both the past and future evolution of our Galaxy. Do star forming regions share global properties, such as initial angular momentum distributions in molecular cloud cores? The frequency, distribution, and properties of young binary stars supply key information. This project is furthering our general understanding of star formation by studying the closest young binary systems in nearby star forming regions. These systems, the spectroscopic binaries, are particularly useful because their radial velocity variations may be measured very precisely and hence their mass ratios and ultimately masses may be accurately determined free of assumptions. The use of high-resolution, infrared spectroscopy for these measurements ensures the identification of even the faintest and lowest mass secondaries in spectroscopic systems. The focus of the proposed projects is on the lower and less well-understood end of the main-sequence. Mass ratio distributions of low-mass spectroscopic binaries will inform us about global characteristics of star formation in different star forming regions. The future determination of absolute masses based on these mass ratios will be crucial for developing accurate models of the formation and evolution of low-mass and substellar objects.Broader impacts: Broad dissemination of results takes the form of publication in refereed journals, press releases, and posters and talks presented at national conferences, enhancing the scientific and technical understanding on the part of the investigator, colleagues, and graduate students. Public access to unique data sets and software applicable to a variety of astrophysical data will be made available on the web.