GEMINI/GMOS SEARCH FOR MASSIVE BINARIES IN THE IONIZING CLUSTER OF 30 DOR
GEMINI/GMOS SEARCH FOR MASSIVE BINARIES IN THE IONIZING CLUSTER OF 30 DOR
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GEMINI/GMOS 在 30 DOR 电离星团中搜索大量双星
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
R. Terlevich
中科院分区：
文献类型：
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作者：
G. Bosch;E. Terlevich;R. Terlevich
如果联星在大质量恒星中很常见，那么它将对星系团年龄、初始质量函数和动力学质量等基本性质的推导产生重要影响。利用双子座多目标摄谱仪的多路复用设备，我们能够调查剑鱼座30电离星团内双星的存在。从一个七个历元的观测活动在南双子座，我们发现一个二元候选人率约为50%，这是一致的大质量恒星之间的内在100%的二元率。我们发现，单历元速度色散的测定给出的值约为30 km s-1。在修正了双星轨道运动的整体速度色散后，“真正的”星团速度色散是8.3 km s−1。这个值意味着维里质量约为4.5 × 105 M，或使用单历元值计算的质量的8%。双星修正的维里质量估计值与测光质量测定值一致，因此表明NGC 2070是未来球状星团的坚定候选者。
If binaries are common among massive stars, it will have important consequences for the derivation of fundamental properties such as the cluster age, initial mass function, and dynamical mass. Making use of the multiplexing facilities of the Gemini Multi-Object Spectrograph, we were able to investigate the presence of binary stars within the ionizing cluster of 30 Doradus. From a seven-epoch observing campaign at Gemini South we detect a binary candidate rate of about 50%, which is consistent with an intrinsic 100% binary rate among massive stars. We find that single-epoch determinations of the velocity dispersion give values around 30 km s−1. After correcting the global velocity dispersion for the binary orbital motions, the “true” cluster velocity dispersion is 8.3 km s−1. This value implies a virial mass of about 4.5 × 105 M☉ or 8% of the mass calculated using the single-epoch value. The binary corrected virial mass estimate is consistent with photometric mass determinations, thus suggesting that NGC 2070 is a firm candidate for a future globular cluster.