The Effect of Density Variations on Elemental Abundance Ratios in Gaseous Nebulae
The Effect of Density Variations on Elemental Abundance Ratios in Gaseous Nebulae
复制标题
密度变化对气态星云元素丰度比的影响
DOI：
10.1086/191330
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发表时间：
1989
影响因子：
8.7
通讯作者：
R. Rubin
中科院分区：
文献类型：
--
作者：
R. Rubin
利用数值分析表明，当星云内气体密度发生变化时，各种确定电子密度的经验方法会给出不同的结果。十一个不同的物种被认为是众所周知的电子密度（Ne）诊断工具的线对比。在密度变化的情况下，Ne的推断值从最低的N+（122/204微米）到最高的C（2+）（1906/1909 A）有一个级数。对于11个物种中的许多物种，推断的密度有一个固定的顺序，而对于其他物种，密度的不同组合可能会有所不同。当有非恒定密度的条件下，它表明，系统的偏差可能会发生在化学丰度比的经验测定。表格材料描绘的最大偏差，可能会发生在一个特定的丰度比在两个组件模型的确定。参考文献51篇。
Using numerical analysis it is demonstrated that when there are changes in gas density within a nebulae various empirical methods for determining the electron density can give different results. Eleven different species are considered which have line pair ratios that are well-known electron density (Ne) diagnostic tools. In the presence of varying density, there is a progression in inferred values of Ne from N+ (122/204 microns) at the lowest to C(2+) (1906/1909 A) at the highest. For many of the 11 species there is a fixed order in the inferred density, while for others the order can change somewhat for different mixes of densities. When there are nonconstant density conditions, it is shown that systematic biases may occur in the empirical determination of chemical abundance ratios. Tabular material is presented that delineates the maximum bias that can occur in the determination of a particular abundance ratio in a two-component model. 51 refs.