盖亚天体测量星表与自行中的长期像差漂移
The Gaia Astrometric Catalogue and Secular Aberration Drift in Proper Motions
AI总结：
本文论证盖亚天体测量星表应在质心天球参考系中构建，无需考虑长期像差漂移项和太阳系质心加速度效应，并解释了与国际天球参考系的一致性及转换到其他参考系的非必要性和实际顾虑。
摘要：
最近的一篇论文证明了恒星自行中存在一项长期像差漂移项，该项在将针对相对于太阳系质心静止的观测者所定义的天体测量星表转换到其他参考系（例如观测者相对于银河系中心静止的参考系）时产生。这种转换需要对太阳系质心的速度进行准确且精确的估计。该论文认为，盖亚星表的构建应考虑这一效应，以及由太阳系质心加速度引起的像差效应。我们则认为，在盖亚天体测量星表的构建中不应考虑这两种效应。我们简要回顾了盖亚星表的参考系、恒星像差和长期像差漂移的概念及其可观测后果。盖亚星表（应当）在质心天球参考系中构建：该参考系的原点位于由底层太阳系历表所定义的太阳系质心。我们解释了尽管存在由太阳系质心加速度引起的自行项，盖亚星表仍与国际天球参考系一致。我们还解释了为何将天体测量转换到观测者相对于银河系中心或遥远宇宙静止的参考系对于恒星运动学的解释并非必要，并且这种转换存在实际上的顾虑。对太阳系质心速度和加速度的估计，尽管作为科学调查的事项很重要，但对于盖亚天体测量星表的构建并非必需。
英文摘要：
A recent paper demonstrated the existence of a secular aberration drift term in stellar proper motions that arises when transforming an astrometric catalogue defined for an observer at rest with respect to the solar system barycentre to some other reference frame in which, for example, the observer is at rest with respect to the Galactic centre. Such a transformation requires an accurate and precise estimate of the velocity of the solar system barycentre. It was argued that the Gaia catalogue construction should account for this effect and also for the aberrational effect due to acceleration of the solar system barycentre. We argue that these two effects should not be accounted for in the construction of the Gaia astrometric catalogue. We briefly review the Gaia catalogue reference frame, the concepts of stellar aberration and secular aberration drift, and their observable consequences. The Gaia catalogue is (and should be) constructed in the Barycentric Celestial Reference System: the reference system with the origin at the solar system barycentre as defined by the underlying solar system ephemerides. We explain that the Gaia catalogue is consistent with the International Celestial Reference System despite the presence of proper motion terms due to the acceleration of the solar system barycentre. We also explain why transformation of the astrometry to a frame in which the observer is at rest with respect to the Galactic centre or distant universe is not needed for the interpretation of stellar kinematics, and that there are practical concerns with such a transformation. The estimation of the velocity and acceleration of the solar system barycentre, although important as a matter of scientific investigation, are not needed for the construction of the Gaia astrometric catalogue.
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