Precise measurement of the fundamental parameters of stellar systems, including mass and radius, depends critically on how well the stellar distances are known. Astrometry from space provides parallax measurements of unprecented accuracy, from which distances can be derived, initially from the Hipparcos mission, with a further refinement of that analysis provided by van Leeuwen in 2007. The publication of the Gaia DR2 catalogue promises a dramatic improvement in the available data. We have recalculated the dynamical masses of a sample of 1 700 close visual binary stars using Gaia DR2 and compared the results with masses derived from both the original and enhanced Hipparcos data. We show the van Leeuwen analysis yields results close to those of Gaia DR2, but the latter are significantly more accurate. We consider the impact of the Gaia DR2 parallaxes on our understanding of the sample of visual binaries.

中文翻译：

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近视双星的盖亚和依帕科斯视差比较及其对确定质量的影响

恒星系统基本参数的精确测量，包括质量和半径，主要取决于对恒星距离的了解程度。来自太空的天体测量提供了前所未有的精确度的视差测量，从中可以推导出距离，最初来自 Hipparcos 任务，并进一步完善了 van Leeuwen 在 2007 年提供的分析。Gaia DR2 目录的发布有望显着改善可用数据。我们使用 Gaia DR2 重新计算了 1700 颗近距离视觉双星样本的动态质量，并将结果与​​源自原始和增强的 Hipparcos 数据的质量进行了比较。我们展示了 van Leeuwen 分析产生的结果接近于 Gaia DR2，但后者明显更准确。