Statistical Constraints for Astrometric Binaries with Nonlinear Motion
Statistical Constraints for Astrometric Binaries with Nonlinear Motion
复制标题
非线性运动天体测量双星的统计约束
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
G. Kaplan
中科院分区：
文献类型：
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作者：
Valeri V. Makarov;G. Kaplan
依巴谷星表中天体测量双星的轨道和质量比的有用约束是从依巴谷和第谷-2的自行差（Δμ）、自行加速度（）和自行二阶导数（）中导出的。它示出了如何，在某些情况下，统计界可以估计的质量的二级组件。两个天体测量双星目录的产生，一个双星具有显着的自行差异和其他的双星与显着的加速度的自行。附录中推导出了天体测量可观测量Δμ、和与轨道根数之间的数学关系。我们发现加速度大但自行差小的恒星和自行差大但加速度不显著的恒星的光谱类型分布之间存在显著差异。前一个样本的光谱类型分布与依巴谷星表中所有恒星的一般分布相同，而后一个样本明显以太阳型恒星为主，明显缺乏蓝色恒星。我们指出，后者包括大多数二进制长周期（长于约6年）。
Useful constraints on the orbits and mass ratios of astrometric binaries in the Hipparcos catalog are derived from the measured proper motion differences of Hipparcos and Tycho-2 (Δμ), accelerations of proper motions (), and second derivatives of proper motions (). It is shown how, in some cases, statistical bounds can be estimated for the masses of the secondary components. Two catalogs of astrometric binaries are generated, one of binaries with significant proper motion differences and the other of binaries with significant accelerations of their proper motions. Mathematical relations between the astrometric observables Δμ, , and and the orbital elements are derived in the appendices. We find a remarkable difference between the distribution of spectral types of stars with large accelerations but small proper motion differences and that of stars with large proper motion differences but insignificant accelerations. The spectral type distribution for the former sample of binaries is the same as the general distribution of all stars in the Hipparcos catalog, whereas the latter sample is clearly dominated by solar-type stars, with an obvious dearth of blue stars. We point out that the latter set includes mostly binaries with long periods (longer than about 6 yr).