arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2007.14414astro-ph.GA
收藏

行星状星云的双丰度光电离模型：确定富金属组分中的氧含量

Bi-abundance photoionization models of planetary nebulae: determining the amount of Oxygen in the metal rich component

V. Gómez-Llanos, C. Morisset

备注：
Accepted for publication in MNRAS
发表信息：
Monthly Notices of the Royal Astronomical Society, staa2157, published 25 July 2020
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

我们研究的假设，高金属丰度块负责的丰度差异发现在行星状星云之间的重组和碰撞激发线获得的值。我们产生网格的光电离模型结合冷金属丰富的团块发射重元素复合线，嵌入在一个正常的金属丰度区域负责的禁线。网格的两个运行参数是团块的金属丰度和它相对于整个星云的体积分数。我们确定密度和温度（从巴尔末跳跃和[OIII] 5007/4363 A线比），和离子丰度从碰撞和重组线，作为一个观察者会做的。近太阳区域的金属丰度得到恢复，而团块的金属丰度被系统地低估，最多可达2个数量级。这主要是因为大多数H $β$发射来自“正常”区域，并且应该仅使用由富含金属的团块发射的小贡献。我们发现，一个给定的ADF（O $^{++}$）可以复制少量的丰富的团块，或大量的不太丰富的团块。最后，与NGC 6153的观测结果进行比较，我们发现有两个模型能再现NGC 6153的ADF（O $^{++}$）和电子温度。我们确定富金属区域中的氧含量（体积分数小于1%）大致在星云中氧总量的25%到60%之间（几个$^{-3} M_\odot$）。

英文摘要：

We study the hypothesis of high metallicity clumps being responsible for the abundance discrepancy found in planetary nebulae between the values obtained from recombination and collisionaly excited lines. We generate grids of photoionization models combining cold metal-rich clumps emitting the heavy element recombination lines, embedded in a normal metallicity region responsible for the forbidden lines. The two running parameters of the grid are the metallicity of the clumps and its volume fraction relative to the whole nebula. We determine the density and temperatures (from the Balmer jump and the [OIII] 5007/4363 A line ratio), and the ionic abundances from the collisional and recombination lines, as an observer would do. The metallicity of the near-to-solar region is recovered, while the metallicity of the clumps is systematically underestimated, by up to 2 orders of magnitude. This is mainly because most of the H$β$ emission is coming from the "normal" region, and only the small contribution emitted by the metal-rich clumps should be used. We find that a given ADF(O$^{++}$) can be reproduced by a small amount of rich clumps, or a bigger amount of less rich clumps. Finally, comparing with the observations of NGC 6153 we find 2 models that reproduce its ADF(O$^{++}$) and the observed electron temperatures. We determine the fraction of oxygen embedded in the metal-rich region (with a fraction of volume less than 1%) to be roughly between 25% and 60% of the total amount of oxygen in the nebula (a few 10$^{-3} M_\odot$).

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。

↑