论文标题
行星星云的双重光电离世模型：确定金属富分量中的氧气量
Bi-abundance photoionization models of planetary nebulae: determining the amount of Oxygen in the metal rich component
论文作者
论文摘要
我们研究了高金属块的假说，是为了使行星星云中从重组和碰撞激发线获得的值之间发现的丰度差异。我们生成的光电离电模型的网格结合了富含冷元素重组线的冷金属团块，该团块嵌入了负责禁止线的正常金属区域。网格的两个运行参数是团块的金属性及其相对于整个星云的体积分数。我们确定密度和温度（从Balmer跳跃和[OIII] 5007/4363 A线比），以及碰撞和重组线的离子丰度，就像观察者一样。恢复了近至 - 极区域的金属性，而团块的金属性则被系统地低估了2个数量级。这主要是因为大多数H $β$排放来自“正常”区域，只有使用富含金属的团块发出的小贡献。我们发现，给定的ADF（o $^{++} $）可以通过少量丰富的团块或大量不丰富的团块来复制。最后，与NGC 6153的观察结果相比，我们发现了2个模型，这些模型重现其ADF（O $^{++} $）和观察到的电子温度。我们确定嵌入金属富含金属区域的氧（体积的比例小于1％）的比例大约在星云中的氧气总量的25％至60％之间（几个10 $^{ - 3} M_ \ odot $）。
We study the hypothesis of high metallicity clumps being responsible for the abundance discrepancy found in planetary nebulae between the values obtained from recombination and collisionaly excited lines. We generate grids of photoionization models combining cold metal-rich clumps emitting the heavy element recombination lines, embedded in a normal metallicity region responsible for the forbidden lines. The two running parameters of the grid are the metallicity of the clumps and its volume fraction relative to the whole nebula. We determine the density and temperatures (from the Balmer jump and the [OIII] 5007/4363 A line ratio), and the ionic abundances from the collisional and recombination lines, as an observer would do. The metallicity of the near-to-solar region is recovered, while the metallicity of the clumps is systematically underestimated, by up to 2 orders of magnitude. This is mainly because most of the H$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$^{-3} M_\odot$).
