Ruprecht 147: A Paradigm of Dissolving Star Cluster
Ruprecht 147: A Paradigm of Dissolving Star Cluster
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DOI：
10.3847/1538-3881/aaff6c
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发表时间：
2019-01
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影响因子：
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通讯作者：
Fungee Yeh;G. Carraro;M. Montalto;A. Seleznev
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作者：
Fungee Yeh;G. Carraro;M. Montalto;A. Seleznev
我们利用最近的GaIA/DR2数据研究了附近(300pC)、旧(2.5Gyr)疏散星系团Ruprecht147的动力学状态。我们在星团轨道上发现了突出的恒星前尾和拖尾，这表明鲁普雷希特147正在以快速的速度失去恒星。恒星计数表明，该星团的核心半径为33.3arcmin，潮汐半径为137.5 arcmin。该星系团还拥有一个扩展的日冕，这是简单的King模型无法复制的。我们利用它的光度和质量函数计算了现在的星系团质量，得到了234±52M⊙的估计值。我们还使用从N-Body模拟中提取的可用食谱估计了星团的原始质量，获得了出生时的质量为50,000±6,500M⊙。因此，动力质量损失，主要是由与银河系的潮汐相互作用引起的，使星系团的质量减少了约99%。然后我们得出结论，Ruprecht147正在迅速地溶解到一般的银河盘中。
We employed recent Gaia/DR2 data to investigate the dynamical status of the nearby (300 pc), old (2.5 Gyr) open cluster Ruprecht 147. We found prominent leading and trailing tails of stars along the cluster orbit, which demonstrates that Ruprecht 147 is losing stars at fast pace. Star counts indicate the cluster has a core radius of 33.3 arcmin and a tidal radius of 137.5 arcmin. The cluster also possesses an extended corona, which cannot be reproduced by a simple King model. We computed the present-day cluster mass using its luminosity and mass function, and derived an estimate of 234 ± 52 M⊙. We also estimated the cluster original mass using available recipes extracted from N-body simulations obtaining a mass at birth of 50,000 ± 6500 M⊙. Therefore dynamical mass loss, mostly caused by tidal interaction with the Milky Way, reduced the cluster mass by about 99%. We then conclude that Ruprecht 147 is rapidly dissolving into the general Galactic disk.