Observational Constraints on Binary Star Formation

这项研究的目的是推导出双星系统形成理论的可靠观测约束。目前对双星系统的整体特征所知甚少，而这些特征与它们的形成有关。特别是，我们不知道双星系统中伴星的质量是否与主星和单星的质量分布方式相同。对于表征双星的轨道角动量的值和范围，人们几乎一无所知。最后一个问题尤为重要，因为双星轨道可能是形成系统的致密云核的原始角动量的储存库，从而有助于形成恒星形成所必需的物质的中心集中。为了纠正这些缺陷，需要对双星整体特征的半长轴和次级/初级质量比的联合分布作出可靠的估计。推导这种分布的方法是统计建模的方法，其中所需的内在特征（半长轴、质量比）的分布与可观测量（轨道周期、速度等）的分布以确定性的方式相关，并保留数据中的所有信息。将使用开发这种模型的数学上严格的方法，以及使用其统计反演的手段，从可观测值推断出所需的内在分布。将给出所有观测到的双星类型（光谱、可见等）的模型轮廓。这些模型将与来自最近和未来对双星系统的观测无偏调查的数据一起使用，以确定半长轴和质量梯度的联合分布，表征均匀主星型双星系统。这些特征的分布可以直接用于确定二级质量函数和轨道角动量值的分布（以及其他动态特征），将双星系统作为一个整体进行表征。所得到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。这将有助于确定目前关于双星形成的理论在多大程度上是正确的，并促进我们对恒星形成过程的总体理解。＊＊＊

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. ***