Massive Stars in the Quintuplet Cluster
Massive Stars in the Quintuplet Cluster
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五重星团中的大质量恒星
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
M. Morris
中科院分区：
文献类型：
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作者：
D. Figer;I. McLean;M. Morris
我们展示了五重星团中新发现的大质量恒星的近红外光度测量和 K 波段光谱，五重星团是投影在银河系中心 50 pc 范围内的三个大质量星团之一。我们发现该星团包含各种大质量恒星，其中包括比银河系任何星团都多的明确识别的沃尔夫-拉叶星，以及十几颗处于演化早期阶段的恒星，即发光蓝变星（LBV）、Ofpe/WN9和OB超巨星。一颗新发现的恒星是星团中第二颗发光的蓝色变星，仅次于“手枪星”。虽然我们无法为这五颗神秘的五联体成员提供某些光谱分类，但我们初步认为它们是在星团其他地方发现的 WC 恒星的尘土飞扬的版本，与银河系中十几个已知的例子相似。尽管由于光度误差和恒星模型（即外推初始质量和估计电离通量）的不确定性，星团参数是不确定的，但我们得出以下结论。考虑到已识别恒星的演化阶段，假设同时形成，该星团的年龄似乎约为 4±1 密尔。假设质量截止值较低为 1 M☉ 和 Salpeter 初始质量函数，观测到的恒星的总质量约为 103 M☉，隐含质量约为 104 M☉。恒星中隐含的质量密度大于或类似于几千M☉ pc-3。新发现的恒星使该星团的估计电离通量比之前的估计增加了大约一个数量级，达到 1050.9 个光子 s-1，或者大约是电离附近“镰刀”H II 区域 (G0.18-0.04) 所需的数量。大质量星团恒星的总光度约为 107.5 L☉，足以解释附近分子云 M0.20-0.033 的加热。我们提出了一张整合了这部分天空的大部分主要特征（非热丝除外）的图片。我们将该星团与其他年轻的大质量星团和球状星团进行比较，发现它在恒星含量和年龄方面是独一无二的，也许除了银河系中央秒差距的年轻星团之外。此外，我们发现该星团与小型“超级星团”相当。
We present near-infrared photometry and K-band spectra of newly identified massive stars in the Quintuplet cluster, one of the three massive clusters projected within 50 pc of the Galactic center. We find that the cluster contains a variety of massive stars, including more unambiguously identified Wolf-Rayet stars than any cluster in the Galaxy, and over a dozen stars in earlier stages of evolution, i.e., luminous blue variables (LBVs), Ofpe/WN9, and OB supergiants. One newly identified star is the second luminous blue variable in the cluster, after the "Pistol star." Although we are unable to provide certain spectral classifications for the five enigmatic Quintuplet-proper members, we tentatively propose that they are extremely dusty versions of the WC stars found elsewhere in the cluster and similar to the dozen or so known examples in the Galaxy. Although the cluster parameters are uncertain because of photometric errors and uncertainties in stellar models, i.e., extrapolating initial masses and estimating ionizing fluxes, we have the following conclusions. Given the evolutionary stages of the identified stars, the cluster appears to be about 4±1 Myr old, assuming coeval formation. The total mass in observed stars is ~103 M☉, and the implied mass is ~104 M☉, assuming a lower mass cutoff of 1 M☉ and a Salpeter initial mass function. The implied mass density in stars is greater than or similar to a few thousand M☉ pc-3. The newly identified stars increase the estimated ionizing flux from this cluster by about an order of magnitude with respect to earlier estimates, to 1050.9 photons s-1, or roughly what is required to ionize the nearby "Sickle" H II region (G0.18-0.04). The total luminosity from the massive cluster stars is ≈107.5 L☉, enough to account for the heating of the nearby molecular cloud, M0.20-0.033. We propose a picture that integrates most of the major features in this part of the sky, excepting the nonthermal filaments. We compare the cluster to other young massive clusters and globular clusters, finding that it is unique in stellar content and age, except, perhaps, for the young cluster in the central parsec of the Galaxy. In addition, we find that the cluster is comparable to small "super star clusters."