论文标题
长期的光电稳定性和包络动力在后AGB二进制系统中89 Herculis
Long-term photospheric instabilities and envelopes dynamics in the post-AGB binary system 89 Herculis
论文作者
论文摘要
我们提出了对后二进制系统89 Herculis的长期光谱研究，目的是表征系统的近距离环境中光球构成和动态之间的关系。 This study is based on spectra acquired with the high-resolution Catania Astrophysical Observatory Spectropolarimeter and archive data, covering a time interval between 1978 and 2018. We find long-term changes in the radial velocity curve of the system, occurring mostly in amplitude, which correlate with the variability observed in the blue-shifted absorption component of the P Cygni like H$α$ profile.讨论了两种可能的情况。我们还发现在\ ion {ba} {ii} $ 6141.713 $Å和$ 6496.898 $Å\ $ 6141.713 $ 6141.713 $ 6141.713 $Å中的S过程中进行了强烈的分裂。这样的轮廓的高斯分解使我们能够区分四个壳体组件，两个壳体成分，两个膨胀和两个向中心恒星倾向，这些恒星受到系统的轨道运动的影响，并且不受长期不稳定性的影响。最后，我们发现发射中的众多金属线可能起源于结构化电路磁盘的区域，该磁盘的大小与相应上层过渡的能量成正比，$ \ rm e_ {up} $。这项研究表明，长期高分辨率光谱法将在后AGB的晚期进化阶段和随后的PNE阶段连接在一起的不稳定性过程中的潜力。
We present a long-term optical spectroscopic study of the post-AGB binary system 89 Herculis, with the aim to characterize the relationship between photospheric instabilities and dynamics in the close circumstellar environment of the system. This study is based on spectra acquired with the high-resolution Catania Astrophysical Observatory Spectropolarimeter and archive data, covering a time interval between 1978 and 2018. We find long-term changes in the radial velocity curve of the system, occurring mostly in amplitude, which correlate with the variability observed in the blue-shifted absorption component of the P Cygni like H$α$ profile. Two possible scenarios are discussed. We also find strong splitting in the s-process elements of \ion{Ba}{ii} $6141.713$ Å and $6496.898$ Å\,lines, with short-term morphological variations. A Gaussian decomposition of such profiles allows us to distinguish four shell components, two expanding and two in-falling toward the central star, which are subject to the orbital motion of the system and are not affected by the long-term instabilities. Finally, we find that the numerous metal lines in emission could originate in regions of a structured circumbinary disk that have sizes proportional to the energy of the corresponding upper level transition $\rm E_{up}$. This study demonstrates the potential of long-term high-resolution spectroscopy in linking together the instability processes occurring during the late evolutionary stages of post-AGBs and the subsequent phase of PNe.
