Active Luminous Blue Variables in the Large Magellanic Cloud
Active Luminous Blue Variables in the Large Magellanic Cloud
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大麦哲伦星云中活跃的发光蓝色变星
DOI：
10.3847/1538-3881/aa6195
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
R. Angeloni
中科院分区：
文献类型：
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作者：
N. Walborn;R. Gamen;N. Morrell;R. Barbá;E. Lajus;R. Angeloni
我们提供了对大麦哲伦星云(LMC)中两个著名的、目前高度活跃的发光蓝色变星(LBV)的广泛光谱和光度监测，并对该类中另外三个鲜为人知的成员进行了更有限的覆盖。R127在20世纪70年代作为Ofpe/WN9恒星被发现，但在1980年左右进入了一次经典的LBV爆发，至今仍在进行中，从而启发了我们对这类天体的最低状态的了解。R71是目前LMC中最明亮的恒星，随着它的光谱类型变得前所未有地晚，它继续带来惊喜，例如[CaII]发射线的出现。最近，R71在许多金属线上开发了反P Cyg轮廓。其他天体如下：HDE 269582，现在是第二个R127，在目前的爆发中已经从OFPE/WN9变为A型；HDE 269216，从2014年底的B变到2016年的AF，这是它第一次观测到的爆发；以及R143，位于剑鱼座30号郊区。光线曲线和光谱变换被非常详细地关联起来，并强调了它们的极端重复性，无论是对于给定的对象还是在所有对象之间。现在人们认为，一些LBV直接导致了核心坍塌。因此，在不久的将来，这些不稳定的LMC天体中的一个可能会这样做，让我们更多地了解大规模恒星演化的最后阶段。
We present extensive spectroscopic and photometric monitoring of two famous and currently highly active luminous blue variables (LBVs) in the Large Magellanic Cloud (LMC), together with more limited coverage of three further, lesser known members of the class. R127 was discovered as an Ofpe/WN9 star in the 1970s but entered a classical LBV outburst in or about 1980 that is still in progress, thus enlightening us about the minimum state of such objects. R71 is currently the most luminous star in the LMC and continues to provide surprises, such as the appearance of [Ca ii] emission lines, as its spectral type becomes unprecedentedly late. Most recently, R71 has developed inverse P Cyg profiles in many metal lines. The other objects are as follows: HDE 269582, now a “second R127” that has been followed from Ofpe/WN9 to A type in its current outburst; HDE 269216, which changed from late B in 2014 to AF in 2016, its first observed outburst; and R143 in the 30 Doradus outskirts. The light curves and spectroscopic transformations are correlated in remarkable detail and their extreme reproducibility is emphasized, both for a given object and among all of them. It is now believed that some LBVs proceed directly to core collapse. One of these unstable LMC objects may thus oblige in the near future, teaching us even more about the final stages of massive stellar evolution.