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arXiv 1008.4178astro-ph.GA
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行星状星云NGC 7009的可见光和红外成像和光谱

Mapping and Spectroscopy of the Planetary Nebula NGC 7009 in the Visual and Infrared

J. P. Phillips, L. Cuesta, G. Ramos-Larios

摘要:

NGC 7009是一个高激发的椭圆行星状星云(PN)的迷人例子,它包含环绕星云的环,以及沿长轴的FLIER和喷流。我们目前的视觉光谱沿着多个位置的角度通过核,与国家天文台(墨西哥);中红外(MIR)光谱和成像使用红外空间天文台(ISO)和斯皮策太空望远镜(SST)获得,并使用哈勃太空望远镜(HST)获得窄带成像。数据表明,中红外(MIR)连续光谱主要是由一个广泛的~ 100 K的连续光谱,和一个强烈的过剩归因于结晶硅酸盐的发射。这种过剩的主峰与镁橄榄石、斜顽火辉石和正顽火辉石中观察到的主峰相似。我们使用地基光谱,和比率的HST图像调查的存在下,在ansae和内部信封的冲击。它的结论是,线比在袢可能是部分一致的冲击激发,虽然这些功能主要是由光电离。我们还注意到在内部椭圆壳的极限处的激波激发的证据,以及以袢为中心的多个弓形激波结构的证据。

英文摘要:

NGC 7009 is a fascinating example of a high excitation, elliptical planetary nebula (PN) containing circum-nebular rings, and FLIERs and jets along the major axis. We present visual spectroscopy along multiple position angles through the nucleus, taken with the Observatorio Astronomico Nacional (Mexico); mid-infrared (MIR) spectroscopy and imaging acquired using the Infrared Space Observatory (ISO) and Spitzer Space Telescope (SST), and narrow band imaging obtained using the Hubble Space Telescope (HST). The data show that the mid-infrared (MIR) continuum is dominated by a broad ~ 100K continuum, and a strong excess attributable to crystalline silicate emission. The primary peaks in this excess are similar to those observed in Forsterite and clino- and ortho-enstatite. We use the ground-based spectroscopy, and ratioing of HST images to investigate the presence of shocks in the ansae and interior envelope. It is concluded that line ratios in the ansae may be partially consistent with shock excitation, although these features are primarily dominated by photo-ionisation. We also note evidence for shock excitation at the limits of the interior elliptical shell, and for multiple bow-shock structures centered upon the ansae.

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