Asymmetric ejecta of cool supergiants and hypergiants in the massive cluster Westerlund 1
Asymmetric ejecta of cool supergiants and hypergiants in the massive cluster Westerlund 1
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大质量星团 Westerlund 1 中冷超巨星和超巨星的不对称喷射物
DOI：
10.1093/mnrasl/sly046
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Andrews H
中科院分区：
文献类型：
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作者：
Andrews H
我们报告了澳大利亚望远镜紧凑阵列对大质量星团 Westerlund 1 进行的新 5.5GHz 射电观测，检测到星团内 10 个黄超巨星 (YHG) 和红超巨星 (RSG) 中的 9 个。九个来源中有八个是空间解析的。与 YHG Wd1-4a、-12a 和 -265 相关的星云表现出彗星形态——这是首次在此类恒星中观察到这种现象。这种结构也反映在 RSG Wd1-20 和 -26 的喷射物中；在每种情况下，彗尾都远离星团核心。 RSG Wd1-237 周围的星云发射不如这些系统准直，但在面向星团的半球中再次显得更加突出。从整体上考虑，星云形态为通过与 Westerlund 1 相关的物理因素（例如星团风）进行雕刻提供了令人信服的证据。
We report new 5.5 GHz radio observations of the massive star cluster Westerlund 1, taken by the Australia Telescope Compact Array, detecting nine of the ten yellow hypergiants (YHGs) and red supergiants (RSGs) within the cluster. Eight of nine sources are spatially resolved. The nebulae associated with the YHGs Wd1-4a, -12a, and -265 demonstrate a cometary morphology – the first time this phenomenon has been observed for such stars. This structure is also echoed in the ejecta of the RSGs Wd1-20 and -26; in each case the cometary tails are directed away from the cluster core. The nebular emission around the RSG Wd1-237 is less collimated than these systems but once again appears more prominent in the hemisphere facing the cluster. Considered as a whole, the nebular morphologies provide compelling evidence for sculpting via a physical agent associated with Westerlund 1, such as a cluster wind.