查看“尘埃”的源代码

*[[消光曲线]]
*发射线的消光可能和连续谱的消光不同
*Halpha/Hbeta 线比
:内禀数值：2.86（恒星形成），3.1（AGN） 参见Osterbrock  & Ferland 2006
*尘埃的红外发射: dustEM
*尘埃与气体有关，气体的光深可以从low-ionization interstellar (IS) absorption lines(e.g., Si II, O I, Fe II)获得 (Shapley et al. 2003)
:e.g. If the two Si II transitions at 1260 and 1527A are optically thin, then the ratio of their equivalent widths will be W1260/W1527 > 6. The observed ratio is W1260/W1527 ~ 1,  implying that the lines are saturated and hence their depths are sensitive to the covering fraction of Si II-enriched material.