论文标题
河马和Gaia天体参考帧的差分适当运动自旋
Differential proper motion spin of the Hipparcos and Gaia celestial reference frames
论文作者
论文摘要
Hipparcos目录提供了光学域中的天体参考框架（CRF）的第一个时期，并用作不可或缺的工具，可用于验证和改善较亮星（$ V <11 $ mag）的Gaia CRF（$ V <11 $ mag），并识别出具有不可思议的二元星星，其中包括带有长期不知所措的伴侣，包括长期period exoperod Exoplanets。河马和盖亚中的位置系统无法直接比较，因为它们指的是两个不同的平均时期。结果表明，在给定的形式错误中，精心过滤的普通恒星的适当运动系统在统计上不一致。适当运动差的向量场与126个矢量球形谐波拟合到第7级，揭示了高信噪比时的全局模式，包括刚性旋转的三个术语。通过产生Gaia $ - $ HG适当运动场的类似分解来研究差异自旋和其他大谐波项的起源，其中HG代表了从Hipparcos和Gaia DR3位置得出的长期适当运动，用于同一恒星样品。 Hipparcos适当的动作成为多上座光学CRF的最大扭曲的最大来源，中位价值为$ \ sim 190 $ $ $ $ $ as yr $^{ - 1} $，全球旋转和$ \ sim 226 $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $按$ \ sim 10 $ $ $ $的构造为yr $^{ - 1} $。但是，后者包括高度的多种变形，应在使用HG场中考虑在天体应用中。
The Hipparcos catalog provides the first epoch of the celestial reference frame (CRF) in the optical domain and serves as an indispensable tool to verify and improve the Gaia CRF for the brighter stars ($V<11$ mag) and to identify the elusive astrometric binary stars with dim or invisible companions, including long-period exoplanets. The systems of positions in Hipparcos and Gaia cannot be directly compared, because they refer to two different mean epochs. It is shown that the proper motion systems for carefully filtered common stars are not statistically consistent within the given formal errors. The vector field of proper motion differences is fitted with 126 vector spherical harmonics up to degree 7 revealing a global pattern at high signal-to-noise ratios, including the three terms of rigid rotation. The origin of the differential spin and other large harmonic terms is investigated by producing a similar decomposition of the Gaia$-$HG proper motion field, where HG stands for the long-term proper motions derived from the Hipparcos and Gaia DR3 positions, for the same sample of stars. Hipparcos proper motions emerge as the largest source of sky-correlated distortions of the multi-epoch optical CRF with a median value of $\sim 190$ $μ$as yr$^{-1}$ and a global spin of $\sim 226$ $μ$as yr$^{-1}$, while the Hipparcos positions and Gaia EDR3 proper motions are explicitly consistent by construction at a level of $\sim 10$ $μ$as yr$^{-1}$. The latter, however, include multiple distortions of higher degree, which should be taken into account in astrometric applications using the HG field.
