Near-infrared spectra of compact planetary nebulae
Near-infrared spectra of compact planetary nebulae
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DOI：
10.1046/j.1365-8711.2001.04868.x
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发表时间：
2001-07
影响因子：
4.8
通讯作者：
S. Lumsden;P. Puxley;M. H. D. O. Physics;Astronomy;U. Leeds;UK.;G. Observatory;Hilo;Hawaii;Usa
中科院分区：
文献类型：
--
作者：
S. Lumsden;P. Puxley;M. H. D. O. Physics;Astronomy;U. Leeds;UK.;G. Observatory;Hilo;Hawaii;Usa
本文继续研究了行星状星云中近红外氦复合线的行为。我们发现1.7007 μm的He i线是He i复合率的一个很好的量度，因为它随中心星星的有效温度平滑地变化。我们无法重现观察到的数据，使用详细的光电离模型在低和高有效温度，但合理的解释存在的差异。因此，我们得出结论，这条线可以作为一个指标的有效温度在被掩盖的星云。我们还表征了在我们的样品的一个较小的子集中存在的分子氢发射的性质。这一结果与以前的数据一致，表明行星状星云中的氢分子发射主要是由紫外激发而不是激波引起的。
This paper continues our study of the behaviour of near-infrared helium recombination lines in planetary nebulae. We find that the 1.7007-μm He i line is a good measure of the He i recombination rate, since it varies smoothly with the effective temperature of the central star. We were unable to reproduce the observed data using detailed photoionization models at both low and high effective temperatures, but plausible explanations for the difference exist for both. We therefore conclude that this line could be used as an indicator of the effective temperature in obscured nebulae. We also characterized the nature of the molecular hydrogen emission present in a smaller subset of our sample. The results are consistent with previous data indicating that ultraviolet excitation rather than shocks is the main cause of the molecular hydrogen emission in planetary nebulae.