A million binaries from Gaia eDR3: sample selection and validation of Gaia parallax uncertainties
A million binaries from Gaia eDR3: sample selection and validation of Gaia parallax uncertainties
复制标题
DOI：
10.1093/mnras/stab323
复制
发表时间：
2021-01
影响因子：
4.8
通讯作者：
K. El-Badry;H. Rix;T. Heintz
中科院分区：
文献类型：
--
作者：
K. El-Badry;H. Rix;T. Heintz
我们从盖亚eDR 3构建一个广泛的目录内的空间分辨双星$\约$1千秒差距的太阳，与投影分离范围从几个Au 1秒差距。我们估计的概率，每一对是一个机会对齐经验，使用盖亚目录本身计算率的机会对齐作为一个函数的观测。该星表包含130万（110万）个结合概率>90%（>99%）的双星，包括16，000个白色矮-主序星（WD+MS）双星和1，400个WD+WD双星。我们公开了完整的星表，以及生成它的查询和代码。然后，我们使用这个样本来校准已发布的Gaia DR 3视差不确定度，利用二进制组件几乎相同的视差。我们表明，这些不确定性一般是可靠的微弱的恒星（$G\gtrsim 18$），但被低估的明亮的恒星。对于具有良好天体测量的孤立源，低估值通常为30%，但对于具有小于4角秒的伴星的明显良好源，低估值更大（高达80%），对于天体测量拟合较差的源，低估值要大得多。我们提供了一个经验拟合函数来夸大孤立源的已发布$\sigma_{\varpi}$值。公共目录提供了广泛的后续机会：从校准光谱调查，以精确地限制场星的年龄，质量和白色矮星的初始-最终质量关系，以动态探测银河系潮汐场。
We construct from Gaia eDR3 an extensive catalog of spatially resolved binary stars within $\approx$ 1 kpc of the Sun, with projected separations ranging from a few au to 1 pc. We estimate the probability that each pair is a chance alignment empirically, using the Gaia catalog itself to calculate the rate of chance alignments as a function of observables. The catalog contains 1.3 (1.1) million binaries with >90% (>99%) probability of being bound, including 16,000 white dwarf -- main sequence (WD+MS) binaries and 1,400 WD+WD binaries. We make the full catalog publicly available, as well as the queries and code to produce it. We then use this sample to calibrate the published Gaia DR3 parallax uncertainties, making use of the binary components' near-identical parallaxes. We show that these uncertainties are generally reliable for faint stars ($G\gtrsim 18$), but are underestimated significantly for brighter stars. The underestimates are generally $\le 30\%$ for isolated sources with well-behaved astrometry, but are larger (up to 80%) for apparently well-behaved sources with a companion within $\lesssim 4$ arcsec, and much larger for sources with poor astrometric fits. We provide an empirical fitting function to inflate published $\sigma_{\varpi}$ values for isolated sources. The public catalog offers wide ranging follow-up opportunities: from calibrating spectroscopic surveys, to precisely constraining ages of field stars, to the masses and the initial-final mass relation of white dwarfs, to dynamically probing the Galactic tidal field.