Confirmation of the Gaia DR2 Parallax Zero-point Offset Using Asteroseismology and Spectroscopy in the Kepler Field
Confirmation of the Gaia DR2 Parallax Zero-point Offset Using Asteroseismology and Spectroscopy in the Kepler Field
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DOI：
10.3847/1538-4357/ab1f66
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发表时间：
2018-05
期刊：
影响因子：
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通讯作者：
J. Zinn;M. Pinsonneault;D. Huber;D. Stello
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文献类型：
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作者：
J. Zinn;M. Pinsonneault;D. Huber;D. Stello
我们提出了一个独立的确认零点偏移的盖亚数据发布2的天文台使用开普勒领域的演化恒星的asteroseismic数据。利用APOKASC-2星表中特征良好的红巨星分支星，我们确定了一个盖亚天体测量假色（ν eff）和盖亚G波段星等相关的零点偏移量，其大小为52.8 ± 2.4（兰德）。± 8.6（系统）−（150.7 ± 22.7）（ν eff − 1.5）−（4.21 ± 0.77）（G − 12.2）μas，在这个意义上，盖亚的弛豫太小了。在高消光和低消光的样本中，以及在壳层燃烧氢的红巨星和核部燃烧氦的红团星中，都发现了这种偏移。我们表明，在小行星地震半径和温度尺度的错误可以区分盖亚视差尺度的错误。我们估计系统的影响，推断全球盖亚视差偏移，c，由于半径和温度系统学，以及在辐射热校正和盖亚视差空间相关性的形式所采用的选择。由于可能存在空间相关的视差误差，正如盖亚团队所讨论的那样，我们的盖亚视差偏移模型是特定于开普勒场的，但与盖亚团队推断的星等和颜色相关偏移以及随后使用独立方法进行的几项调查广泛兼容。
We present an independent confirmation of the zero-point offset of Gaia Data Release 2 parallaxes using asteroseismic data of evolved stars in the Kepler field. Using well-characterized red giant branch stars from the APOKASC-2 catalog, we identify a Gaia astrometric pseudocolor ( ν eff )- and Gaia G-band magnitude-dependent zero-point offset of ϖ seis − ϖ Gaia = 52.8 ± 2.4 (rand.) ± 8.6 (syst.) − (150.7 ± 22.7)( ν eff − 1.5) − (4.21 ± 0.77)(G − 12.2) μas, in the sense that Gaia parallaxes are too small. The offset is found in high- and low-extinction samples, as well as among both shell H-burning red giant stars and core He-burning red clump stars. We show that errors in the asteroseismic radius and temperature scales may be distinguished from errors in the Gaia parallax scale. We estimate systematic effects on the inferred global Gaia parallax offset, c, due to radius and temperature systematics, as well as choices in bolometric correction and the adopted form for Gaia parallax spatial correlations. Because of possible spatially correlated parallax errors, as discussed by the Gaia team, our Gaia parallax offset model is specific to the Kepler field, but broadly compatible with the magnitude- and color-dependent offset inferred by the Gaia team and several subsequent investigations using independent methods.