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arXiv 2312.03211astro-ph.SR
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围绕磁性O型星HD 148937的神秘发射星云NGC 6164/5的形态—运动学研究

A Morpho-Kinematic Study of the Enigmatic Emission Nebula NGC 6164/5 Surrounding the Magnetic O-type Star HD 148937

Beomdu Lim, Yael Naze, Seok-Jun Chang, Damien Hutsemekers

AI总结:

本研究利用VLT/GIRAFFE高分辨率光谱观测并结合Monte-Carlo辐射转移模型,揭示NGC 6164/5的双向外流与膨胀壳层结构,估算其速度和年龄,并探讨双星相互作用成因。

摘要:

HD 148937是一颗具有强磁场(1 kG)的特殊大质量恒星(Of?p)。沙漏形发射星云NGC 6164/5围绕着这颗恒星。该星云被认为起源于中央O型星的间歇性质量损失事件,但其详细形成机制尚不清楚。掌握其三维结构对于揭示该星云的起源至关重要。本文报道了利用8.2米甚大望远镜上的GIRAFFE对NGC 6164/5进行的高分辨率多目标光谱观测。由多条谱线构建的积分强度图清晰勾勒出该星云的整体形状,例如两个明亮瓣片和内部气体区域。位置—速度图显示,两个明亮瓣片分别呈现红移和蓝移,而内部区域具有多个层次。我们考虑了一个几何模型,该模型由包含富氮结的双向外流和正在膨胀的内壳组成。随后,针对不同的速度组合,使用Monte-Carlo辐射转移技术模拟了其光谱特征。模拟得到的一些位置—速度图与观测结果非常相似。根据最能重现观测数据的模型,两个明亮瓣片和富氮结正以约120 km s$^{-1}$的速度远离HD 148937。它们的最小运动学年龄估计约为7,500年。我们在双星相互作用的背景下讨论了该星云可能的形成机制。

英文摘要:

HD 148937 is a peculiar massive star (Of?p) with a strong magnetic field (1kG). The hourglass-shaped emission nebula NGC 6164/5 surrounds this star. This nebula is presumed to originate from episodic mass-loss events of the central O-type star, but the detailed formation mechanism is not yet well understood. Grasping its three-dimensional structure is essential to uncover the origin of this nebula. Here we report the high-resolution multi-object spectroscopic observation of NGC 6164/5 using the GIRAFFE on the 8.2m Very Large Telescope. Integrated intensity maps constructed from several spectral lines delineate well the overall shape of this nebula, such as the two bright lobes and the inner gas region. The position-velocity diagrams show that the two bright lobes are found to be redshifted and blueshifted, respectively, while the inner region has multiple layers. We consider a geometric model composed of a bilateral outflow harboring nitrogen-enriched knots and expanding inner shells. Its spectral features are then simulated by using a Monte-Carlo radiative transfer technique for different sets of velocities. Some position-velocity diagrams from simulations are very similar to the observed ones. According to the model that best reproduces the observational data, the two bright lobes and the nitrogen-enriched knots are moving away from HD 148937 at about 120 km s$^{-1}$. Their minimum kinematic age is estimated to be about 7,500 years. We discuss possible formation mechanisms of this nebula in the context of binary interaction.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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