论文标题
在过渡阶段中四个巨星的近红外表征
Near-infrared characterization of four massive stars in transition phases
论文作者
论文摘要
巨大的恒星通常会发生短暂的后序列序列进化阶段，具有强大的质量损失和偶尔的质量喷发。过渡阶段中的许多巨大恒星都根据其尘土飞扬的信封被鉴定出来。弹出的材料通常会遮盖出恒星的光球，因此中心星无法分配适当的光谱类型和进化阶段。事实证明，红外光谱范围非常适合分类不断发展的巨大恒星和环境的表征。为了提高我们对四个这样的灰尘包含物体的中心恒星的知识：[GKF2010] MN 83，[GKF2010] MN 108，[GKF2010] MN 109和[GKF2010] MN 112，我们收集并提出了他们的第一个中等分辨率K-Band Spectra在$ 2.3 \，2.3 \，2.47 $ \，2.47的位置中，颜色图。我们发现Mn 83和Mn 112的发射线光谱显示出在发光蓝色变量（LBV）恒星中通常可见的特征。此外，我们建议新报告的MG II系的存在和强度可以用作识别LBV候选者的新互补标准。其他两个对象的光谱暗示MN 108是O型超级巨头，而MN 109可能是其活性阶段的LBV候选者。我们得出了朝着恒星变红的下限，发现所有脱落的三个掉落落入确认的LBV区域。
Massive stars typically undergo short-lived post-main sequence evolutionary phases with strong mass loss and occasional mass eruptions. Many of such massive stars in transition phases have been identified based on their dusty envelopes. The ejected material often veils the stellar photospheres so that the central stars cannot be assigned proper spectral types and evolutionary stages. The infrared spectral range has proved to be ideal for the classification of evolved massive stars and for the characterization of their environments. To improve our knowledge on the central stars of four such dust enshrouded objects: [GKF2010] MN 83, [GKF2010] MN 108, [GKF2010] MN 109, and [GKF2010] MN 112, we collect and present their first medium resolution K-band spectra in the $2.3\,-\,2.47\,μ$m region and discuss the location of the stars in the JHK color-color diagram. We find that the emission-line spectra of both MN 83 and MN 112 show characteristics typically seen in Luminous Blue Variable (LBV) stars. In addition, we propose that the presence and strength of the newly reported Mg II lines might be used as a new complementary criterion to identify LBV candidates. The spectra of the other two objects imply that MN 108 is an O-type supergiant, whereas MN 109 could be an LBV candidate in its active phase. We derive lower limits for the reddening toward the stars and find that three of all de-reddened fall into the region of confirmed LBVs.
