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arXiv 1209.6370astro-ph.GA
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模糊的星团。IV。[DBS2003] 179中最大质量的恒星

Obscured clusters.IV. The most massive stars in [DBS2003]179

J. Borissova, L. Georgiev, M. M. Hanson, J. R. A. Clarke, R. Kurtev, V. D. Ivanov, F. Penaloza, D. J. Hillier, J. Zsargo

摘要:

目标。我们报告的年轻星系团DBS2003 179的大规模发展和主序星成员的新结果。我们确定的物理参数和调查的大质量恒星的内容,以及它的近邻。方法.我们的分析是基于ISAAC/VLT中等分辨率(R \approx 4000)红外光谱的最亮的集群成员。我们推导出恒星的16个成员的恒星参数,使用完整的非LTE建模所获得的光谱。结果该星团包含三颗晚期WN或WR/LBV星(Obj 4、Obj 15和Obj 20:MDM32)和至少5颗OIf和5颗OV星。根据DBS2003 179的赫兹-罗素图,WR星的质量在85 Msun以上,OIf星的质量在40 - 80 Msun之间,主序星O的质量大于20 Msun。Obj 4和Obj 11有二元性的迹象,Obj 3显示了一个可变的光谱。该星团被一个连续的原恒星形成区包围,最有可能是由DBS 2003 179触发的。结论.我们确认DBS2003179是一个年轻的大质量星系团(2.5 × 10^4Msun),距离银河系中心7.9 ± 0.8kpc。

英文摘要:

Aims. We report new results for the massive evolved and main sequence members of the young galactic cluster DBS2003 179. We determine the physical parameters and investigate the high-mass stellar content of the cluster, as well as of its close vicinity. Methods. Our analysis is based on ISAAC/VLT moderate-resolution (R\approx4000) infrared spectroscopy of the brightest cluster members. We derive stellar parameters for sixteen of the stellar members, using full non-LTE modeling of the obtained spectra. Results. The cluster contains three late WN or WR/LBV stars (Obj 4, Obj 15, and Obj 20:MDM32) and at least 5 OIf and 5 OV stars. According to the Hertzsprung-Russell diagram for DBS2003 179, the WR stars show masses above 85Msun, the OIf stars are between 40 and 80Msun, and the main sequence O stars are >20Msun. There are indications of binarity for Obj 4 and Obj 11, and Obj 3 shows a variable spectrum. The cluster is surrounded by a continuous protostar formation region most probably triggered by DBS2003 179. Conclusions. We confirm that DBS2003 179 is young massive cluster (2.5 10^4Msun) very close to the Galactic center at the distance of 7.9+-0.8 kpc.

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