Aberration in proper motions for stars in our Galaxy
Aberration in proper motions for stars in our Galaxy
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DOI：
10.1093/mnras/stt1006
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发表时间：
2013-06
影响因子：
4.8
通讯作者：
Jia-cheng Liu;Yi Xie;Zi Zhu
中科院分区：
文献类型：
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作者：
Jia-cheng Liu;Yi Xie;Zi Zhu
太阳系质心（SSB）和银河系内恒星的加速度对恒星固有运动产生了系统的观测效应，这一效应最早是在20世纪90年代初由J. Kovalevsky （aberration in固有运动，2003，AA）提出的，主要由银河系中心区域恒星的加速度所主导。在距银河系中心200pc的范围内，应用平坦的旋转曲线，系统的固有运动可以达到大于1000 μ s/年的振幅。在银河系核心区域线性上升的更为真实的旋转曲线中，像差固有运动被限制在150 μ s/年左右。然后，我们研究了有关像差固有运动的理论表达式的适用性，特别是对于那些具有短周期轨道的恒星。如果恒星的轨道周期只是恒星到SSB的光时的一小部分，那么Kovalevsky提出的表达式是不合适的。用一个更合适的公式，我们发现像差对确定天球上的恒星轨道没有影响。在未来的高精度天文测量中，特别是在构建由银河系恒星实现的盖亚天体参考系统中，所考虑的像差效应很小，但不可忽略。
Accelerations of both the solar system barycenter (SSB) and stars in the Milky Way cause a systematic observational effect on the stellar proper motions, which was first studied in the early 1990s and developed by J. Kovalevsky (aberration in proper motions, 2003, AA it is dominated by the acceleration of stars in the central region of the Galaxy. Within 200 pc from the Galactic center, the systematic proper motion can reach an amplitude larger than 1000 uas/yr by applying a flat rotation curve. With a more realistic rotation curve which is linearly rising in the core region of the Galaxy, the aberrational proper motions are limited up to about 150 uas/yr. Then we investigate the applicability of the theoretical expressions concerning the aberrational proper motions, especially for those stars with short period orbits. If the orbital period of stars is only a fraction of the light time from the star to the SSB, the expression proposed by Kovalevsky is not appropriate. With a more suitable formulation, we found that the aberration has no effect on the determination of the stellar orbits on the celestial sphere. The aberrational effect under consideration is small but not negligible with high-accurate astrometry in the future, particularly in constructing the Gaia celestial reference system realized by Galactic stars.