Kinematic Structure of the Galactic Center S Cluster
Kinematic Structure of the Galactic Center S Cluster
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DOI：
10.3847/1538-4357/ab93ae
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发表时间：
2020-06
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影响因子：
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通讯作者：
B. Ali;D. Paul;A. Eckart;M. Parsa;M. Zajaček;F. Peißker;M. Subroweit;M. Valencia-S.;Lauritz Thomkins;G. Witzel
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作者：
B. Ali;D. Paul;A. Eckart;M. Parsa;M. Zajaček;F. Peißker;M. Subroweit;M. Valencia-S.;Lauritz Thomkins;G. Witzel
我们对112颗恒星的运动学进行了详细的分析，这些恒星主要包括高速S星团和银河系中心的超大质量黑洞Sgr A*。其中39个已知轨道根数，其余的已知自行。倾角和自行飞行方向的分布明显偏离均匀分布，如果轨道的方向是随机的，人们会期望均匀分布。在中央角秒的范围内，S星团的恒星排列成两个几乎是边对边的圆盘，位置与银道面成±45°角。每个圆盘中恒星的角动量矢量指向两个方向，即，在一个给定的圆盘中的恒星以相反的方式旋转。该结构的极点位于距离视线仅约25°的位置。这种结构可能是一个共振过程的结果，该过程始于大约600万年前星团中年轻B矮星的形成。或者，它表明在离中心的距离与紧凑星协IRS 13的距离相当的干扰星的存在。
We present a detailed analysis of the kinematics of 112 stars that mostly comprise the high-velocity S cluster and orbit the supermassive black hole Sgr A* at the center of the Milky Way. For 39 of them, orbital elements are known; for the remainder, we know proper motions. The distribution of the inclinations and the proper motion flight directions deviate significantly from a uniform distribution, which one expects if the orientation of the orbits are random. Across the central arcseconds, the S-cluster stars are arranged in two almost edge-on disks that are located at a position angle approximately ±45° with respect to the Galactic plane. The angular momentum vectors for stars in each disk point in both directions, i.e., the stars in a given disk rotate in opposite ways. The poles of this structure are located only about 25° from the line of sight. This structure may be the result of a resonance process that started with the formation of the young B-dwarf stars in the cluster about 6 Myr ago. Alternatively, it indicated the presence of a disturber at a distance from the center comparable to the distance of the compact stellar association IRS 13.