Observational Constraints on Binary Star Formation

双星形成的观测限制

• 批准号: 9526034
• 负责人: William Heacox
• 金额: $ 7.44万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-05-15 至 1998-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9526034&HistoricalAwards=false
• 关键词: Observational; Constraints; Binary; Star; Formation

9526034 Heacox The objective of the research to be carried is to deduce reliable observational constraints on the theories of the formation of binary star systems. There is very little currently known about the overall binary stellar system characteristics which are relevant to their formation. In particular, we do not know whether the masses of the secondary stars in binary systems are distributed in the same manner as those of primary and single stars. There is almost no knowledge of the values and ranges of the orbital angular momenta values characterizing binary stars. This last issue is particularly important, since binary star orbits may act as the repositories of the original angular momentum of the dense cloud cores from which the systems form, thus aiding in the formation of the central concentration of material necessary for star formation. A reliable estimate of the joint distribution of semi-major axes and secondary/primary mass ratios, characterizing binaries as a whole, is needed to correct these deficiencies. The method for deducing this distribution is that of statistical modeling, wherein the distributions of the desired intrinsic characteristics (semi-major axes, mass ratios) are related to those of the observable quantities (orbital periods, velocities, etc.) in a deterministic manner that preserves all the information in the data. Mathematically rigorous methods of developing such models will be used, as well as the use of the means of their statistical inversion, to infer the desired intrinsic distribution from that of the observables. Model outlines will be given for all observational binary star types (spectroscopic, visible, etc.). These models will be used with the data, from recent and future observationally unbiased surveys of binary star systems, to determine the joint distributions of semi-major axes and mass rat ios characterizing binary star systems of homogeneous primary types. These distributions of characteristics may then be used to directly determine the secondary mass function and distribution of orbital angular momentum values (and other dynamic characteristics) characterizing binary star systems as a whole. The resulting distributions will constitute the first truly meaningful observational constraints on the dominant mode of star formation (most stars are members of binary systems). This will help to determine the extent to which any of the current theories of binary star formation are correct, and advance our understanding of the process of star formation in general. ***

9526034 Heacox 进行这项研究的目的是推断出对双星系统形成理论的可靠观测约束。目前对于与其形成相关的双星系统的总体特征知之甚少。 特别是，我们不知道双星系统中次星的质量分布是否与主星和单星的质量分布相同。 对于表征双星的轨道角动量值的值和范围几乎一无所知。 最后一个问题尤其重要，因为双星轨道可能充当系统形成的致密云核原始角动量的储存库，从而有助于形成恒星形成所需的中心物质集中。 需要对半长轴的联合分布和次要/主要质量比进行可靠的估计，以表征双星的整体特征，以纠正这些缺陷。 推导该分布的方法是统计建模，其中所需固有特性（半长轴、质量比）的分布以确定性方式与可观测量（轨道周期、速度等）的分布相关。保留数据中的所有信息。 将使用开发此类模型的严格数学方法，以及使用其统计反演方法，从可观测值的分布中推断出所需的内在分布。 将为所有观测双星类型（光谱、可见等）给出模型轮廓。 这些模型将与来自最近和未来双星系统观测无偏调查的数据一起使用，以确定表征同质主类型双星系统的半长轴和质量比的联合分布。 然后，这些特性分布可用于直接确定表征双星系统整体的次级质量函数和轨道角动量值的分布（以及其他动态特性）。 由此产生的分布将构成对恒星形成的主要模式（大多数恒星是双星系统的成员）的第一个真正有意义的观测约束。 这将有助于确定当前双星形成理论的正确程度，并增进我们对恒星形成过程的总体理解。 ***