arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1301.3149astro-ph.GAastro-ph.SR
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Kn 26,一个新的四极行星状星云

Kn 26, a New Quadrupolar Planetary Nebula

Martin A. Guerrero, Luis F. Miranda, Gerardo Ramos-Larios, Roberto Vazquez

摘要:

Kn 26曾经被归类为发射线源,但其行星状星云(PN)的性质直到最近才在数字巡天中得到确认。为了研究Kn 26的光谱特性和空间运动学结构,我们获得了高空间分辨率的光学和近红外窄带图像,高色散长缝阶梯光谱,和中等分辨率的光谱观测。新的数据揭示了双极PNe的典型沙漏形态。其形态学和运动学的详细分析揭示了第二对双极叶的存在,使Kn 26的四极PNe子类的新成员。两对双极叶喷射之间的时间间隔比它们的动力学年龄小得多,这意味着中央引擎的优先方向发生了快速变化。Kn 26的化学成分在PNe中特别不寻常,具有低的N/O比(如II型PNe)和高的氦丰度(如I型PNe),尽管在共生星中并不典型。这种异常的化学成分可能是由于祖星通过一个共同的包络相演化而缩短了渐近巨星分支的时间。

英文摘要:

Once classified as an emission line source, the planetary nebula (PN) nature of the source Kn 26 has been only recently recognized in digital sky surveys. To investigate the spectral properties and spatio-kinematical structure of Kn 26, we have obtained high spatial-resolution optical and near-IR narrow-band images, high-dispersion long-slit echelle spectra, and intermediate-resolution spectroscopic observations. The new data reveal an hourglass morphology typical of bipolar PNe. A detailed analysis of its morphology and kinematics discloses the presence of a second pair of bipolar lobes, making Kn 26 a new member of the subclass of quadrupolar PNe. The time-lap between the ejection of the two pairs of bipolar lobes is much smaller than their dynamical ages, implying a rapid change of the preferential direction of the central engine. The chemical composition of Kn 26 is particularly unusual among PNe, with a low N/O ratio (as of type II PNe) and a high helium abundance (as of type I PNe), although not atypical among symbiotic stars. Such an anomalous chemical composition may have resulted from the curtail of the time in the Asymptotic Giant Branch by the evolution of the progenitor star through a common envelope phase.

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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