Revealing evolved massive stars with Spitzer
Revealing evolved massive stars with Spitzer
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斯皮策望远镜揭示演化的大质量恒星
DOI：
10.1111/j.1365-2966.2010.16496.x
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发表时间：
2009
影响因子：
4.8
通讯作者：
S. Fabrika
中科院分区：
文献类型：
--
作者：
V. Gvaramadze;A. Kniazev;S. Fabrika
大质量的演化恒星通过大量的恒星风或瞬间爆发失去了大部分质量。在某些演化阶段，它们可以通过其星周星云的存在来识别。在本文中，我们提出了一个紧凑的星云（让人联想到周围的大质量恒星演化的星周星云）使用档案24 μm的数据获得的斯皮策多波段成像光度计的搜索结果。我们已经发现了115个星云，其中大多数与银河系和大麦哲伦云（LMC）中与亮蓝变星（LBV）和晚期WN型（WNL）沃尔夫-拉叶（WR）星相关的星周星云有着惊人的相似之处。我们将这种相似性解释为一种迹象，即探测到的星云的中心恒星要么是LBV，要么是相关的大质量恒星。我们的解释得到了24颗中心恒星的后续光谱的支持，其中大多数是候选LBV（cLBV），蓝超巨星或WNL恒星。我们预计，即将到来的光谱从我们的名单上剩余的对象，伴随着已经发现的cLBV的分光光度监测，将进一步增加已知的银河系LBV的人口。反过来，这将对更好地理解LBV现象及其在燃烧氢的O型星和燃烧氦的WR型星之间的过渡中的作用产生深远的影响。我们还报告了在LMC中检测到连接到cLBV HD 326823的弧形结构和与LBV R99（HD 269445）相关的弧形结构。
Massive evolved stars lose a large fraction of their mass via copious stellar wind or instant outbursts. During certain evolutionary phases, they can be identified by the presence of their circumstellar nebulae. In this paper, we present the results of a search for compact nebulae (reminiscent of circumstellar nebulae around evolved massive stars) using archival 24-μm data obtained with the Multiband Imaging Photometer for Spitzer. We have discovered 115 nebulae, most of which bear a striking resemblance to the circumstellar nebulae associated with luminous blue variables (LBVs) and late WN-type (WNL) Wolf-Rayet (WR) stars in the Milky Way and the Large Magellanic Cloud (LMC). We interpret this similarity as an indication that the central stars of detected nebulae are either LBVs or related evolved massive stars. Our interpretation is supported by follow-up spectroscopy of two dozen of these central stars, most of which turn out to be either candidate LBVs (cLBVs), blue supergiants or WNL stars. We expect that the forthcoming spectroscopy of the remaining objects from our list, accompanied by the spectrophotometric monitoring of the already discovered cLBVs, will further increase the known population of Galactic LBVs. This, in turn, will have profound consequences for better understanding the LBV phenomenon and its role in the transition between hydrogen-burning O stars and helium-burning WR stars. We also report on the detection of an arc-like structure attached to the cLBV HD 326823 and an arc associated with the LBV R99 (HD 269445) in the LMC.